,state of ,connecticut ,state ,geological and ,natural ,history ,survey ,bulletin ,no4 #cj ,drainage ,modifications and ,glaciation in the ,danbury ,region ,connecticut ,by ,,ruth ,,sawyer ,,harvey1 ,ph4 ,d4 ,,hartford ,published by the ,state #aibj ,,bulletins ,,of ,,the ,state ,geological and ,natural ,history ,survey of ,connecticut4 #a4 ,first ,biennial ,report of the ,commissioners of the ,state ,geological and ,natural ,history ,survey1 #aijc-aijd4 #b4 ,a ,preliminary ,report on the ,protozoa of the ,fresh ,waters of ,connecticut3 by ,herbert ,william ,conn4 7,out of print4 ,to be obtained only in ,vol4 ,i1 containing ,bulletins #a-e4 ,price #a4ej1 postpaid47 #c4 ,a ,preliminary ,report on the ,hymeniales of ,connecticut3 by ,edward ,albert ,white4 #d4 ,the ,clays and ,clay ,industries of ,connecticut3 by ,gerald ,francis ,loughlin4 #e4 ,the ,ustilagineae1 or ,smuts1 of ,connecticut3 by ,george ,perkins ,clinton4 #f4 ,manual of the ,geology of ,connecticut3 by ,william ,north ,rice and ,herbert ,ernest ,gregory4 7,out of print4 ,to be obtained only in ,vol4 ,,ii1 containing ,bulletins #f-ab4 ,price #b4de1 postpaid47 #g4 ,preliminary ,geological ,map of ,connecticut3 by ,herbert ,ernest ,gregory and ,henry ,hollister ,robinson4 #h4 ,bibliography of ,connecticut ,geology3 by ,herbert ,ernest ,gregory4 #i4 ,second ,biennial ,report of the ,commissioners of the ,state ,geological and ,natural ,history ,survey1 #aije-aijf4 #aj4 ,a ,preliminary ,report on the ,algae of the ,fresh ,waters of ,connecticut3 by ,herbert ,william ,conn and ,lucia ,washburn 7,hazen7 ,webster4 #aa4 ,the ,bryophytes of ,connecticut3 by ,alexander ,william ,evans and ,george ,elwood ,nichols4 #ab4 ,third ,biennial ,report of the ,commissioners of the ,state ,geological and ,natural ,history ,survey1 #aijg-aijh4 #ac4 ,the ,lithology of ,connecticut3 by ,joseph ,barrell and ,gerald ,francis ,loughlin4 #ad4 ,catalogue of the ,flowering ,plants and ,ferns of ,connecticut growing without cultivation3 by a ,committee of the ,connecticut ,botanical ,society4 #ae4 ,second ,report on the ,hymeniales of ,connecticut3 by ,edward ,albert ,white4 #af4 ,guide to the ,insects of ,connecticut3 prepared under the direction of ,wilton ,everett ,britton4 ,part ,i4 ,general ,introduction3 by ,wilton ,everett ,britton4 ,part ,,ii4 ,the ,euplexoptera and ,orthoptera of ,connecticut3 by ,benjamin ,hovey ,walden4 #ag4 ,fourth ,biennial ,report of the ,commissioners of the ,state ,geological and ,natural ,history ,survey1 #aiji-aiaj4 #ah4 ,triassic ,fishes of ,connecticut3 by ,charles ,rochester ,eastman4 #ai4 ,echinoderms of ,connecticut3 by ,wesley ,roscoe ,coe4 #bj4 ,the ,birds of ,connecticut3 by ,john ,hall ,sage and ,louis ,bennett ,bishop1 assisted by ,walter ,parks ,bliss4 #ba4 ,fifth ,biennial ,report of the ,commissioners of the ,state ,geological and ,natural ,history ,survey1 #aiaa-aiab4 #bb4 ,guide to the ,insects of ,connecticut3 prepared under the direction of ,wilton ,everett ,britton4 ,part ,,iii4 ,the ,hymenoptera1 or ,wasp-like ,insects1 of ,connecticut3 by ,henry ,lorenz ,viereck1 with the collaboration of ,alexander ,dyer ,mac,gillivray1 ,charles ,thomas ,brues1 ,william ,morton ,wheeler1 and ,sievert ,allen ,rohwer4 #bc4 ,central ,connecticut in the ,geologic ,past3 by ,joseph ,barrell4 #bd4 ,triassic ,life of the ,connecticut ,valley3 by ,richard ,swann ,lull4 #be4 ,sixth ,biennial ,report of the ,commissioners of the ,state ,geological and ,natural ,history ,survey1 #aiac-aiad4 #bf4 ,the ,arthrostraca of ,connecticut3 by ,beverly ,waugh ,kunkel4 #bg4 ,seventh ,biennial ,report of the ,commissioners of the ,state ,geological and ,natural ,history ,survey1 #aiae-aiaf4 #bh4 ,eighth ,biennial ,report of the ,commissioners of the ,state ,geological and ,natural ,history ,survey1 #aiag-aiah4 #bi4 ,the ,quaternary ,geology of the ,new ,haven ,region1 ,connecticut3 by ,freeman ,ward1 ,ph4,d4 #cj4 ,drainage1 ,modification and ,glaciation in the ,danbury ,region1 ,connecticut3 by ,ruth ,sawyer ,harvey1 ,ph4,d4 #ca4 ,check ,list of the ,insects of ,connecticut3 by ,wilton ,everett ,britton1 ,ph4,d4 7,in press47 ,bulletins #a1 #i1 #ab1 #ag1 #ba1 #be1 #bg1 and #bh are merely administrative reports containing no scientific matter4 ,the other bulletins may be classified as follows3 ,geology3 ,bulletins #d1 #f1 #g1 #h1 #ac1 #ah1 #bc1 #bd1 #bi1 #cf4 ,botany3 ,bulletins #c1 #e1 #aj1 #aa1 #ad1 #ae4 ,zooelogy3 ,bulletins #b1 #af1 #ai1 #bj1 #bb1 #bf1 #ca4 ,these bulletins are sold and otherwise distributed by the ,state ,librarian4 ,postage1 when bulletins are sent by mail1 is as follows3 ,no4 #a #j4ja ,no4 #ac #j4jh ,no4 #bc #j4jc #c 4#jh #ad 4#af #bd 4#aj #d 4#jf #ae 4#jf #be 4#jb #e 4#jc #af 4#jg #bf 4#jf #g 4#jf #ag 4#jb #bg 4#jb #h 4#je #ah 4#jg #bh 4#jb #i 4#jb #ai 4#jh #bi 4#jc #aj 4#jh #bj 4#ad #cj 4#jc #aa 4#jg #ba 4#jb #ca #ab 4#jb #bb 4#jh ,the prices when the bulletins are sold are as follows1 postpaid3 ,no4 #a #j4je ,no4 #ac #j4dj ,no4 #bc #j4ae #c 4#dj #ad 4#ge #bd 4#fe #d 4#cj #ae 4#ce #be 4#je #e 4#ae #af 4#ce #bf 4#hj #g 4#fj #ag 4#je #bg 4#je #h 4#bj #ah 4#be #bh 4#je #i 4#je #ai 4#de #bi 4#ej #aj 4#ce #bj 4#ej #cj 4#de #aa 4#cj #ba 4#je #ca #ab 4#je #bb #b4jj ,a part of the edition of these ,bulletins have been assembled in volumes substantially bound in cloth1 plainly lettered1 and sell for the following prices1 postpaid3 ,volume ,i1 containing ,bulletins #a-e #a4ej ,volume ,,ii1 containing ,bulletins #f-ab #b4de ,volume ,,iii1 containing ,bulletins #ac-ae #b4ej ,volume ,,iv1 containing ,bulletins #af-ba #b4ae ,volume ,v1 containing ,bulletin #bb #b4ej ,it is intended to follow a liberal policy in gratuitously distributing these publications to public libraries1 colleges1 and scientific institutions1 and to scientific men1 teachers1 and others who require particular bulletins for their work1 especially to those who are citizens of ,connecticut4 ,applications or inquiries should be addressed to ,george ,s4 ,godard1 ,state ,librarian1 ,hartford1 ,conn4 ,in addition to the bulletins above named1 published by the ,state survey1 attention is called to three publications of the ,united ,states ,geological ,survey prepared in co-operation with the ,geological and ,natural ,survey of ,connecticut4 ,these are the following3 ,bulletin #dhd4 ,the ,granites of ,connecticut3 by ,t4 ,nelson ,dale and ,herbert ,e4 ,gregory4 ,water-,supply ,paper #cgd4 ,ground ,water in the ,hartford1 ,stamford1 ,salisbury1 ,willimantic and ,saybrook ,areas1 ,connecticut3 by ,herbert ,e4 ,gregory and ,arthur ,j4 ,ellis4 ,water-,supply ,paper #cig4 ,ground ,water in the ,waterbury ,area1 ,connecticut3 by ,arthur ,j4 ,ellis1 under the direction of ,herbert ,e4 ,gregory4 ,these papers may be obtained from the ,director of the ,united ,states ,geological ,survey at ,washington4 ,,catalogue ,,slips4 ,connecticut4 ,state geological and natural history survey4 ,bulletin no4 #cj4 ,drainage ,modifications and ,glaciation in the ,danbury ,region1 ,connecticut4 ,by ,ruth ,s4 ,harvey1 ,ph4,d4 ,hartford1 #aibj4 #ei pp41 #e pls41 #aj fig41 #be;cm4 ,harvey1 ,ruth ,sawyer1 ,ph4,d4 ,drainage ,modification and ,glaciation in the ,danbury ,region1 ,connecticut4 ,by ,ruth ,s4 ,harvey1 ,ph4,d4 ,hartford1 #aibj4 #ei pp41 #e pls41 #aj figs41 #be;cm4 ,geology4 ,harvey1 ,ruth ,s4 ,drainage ,modifications and ,glaciation in the ,danbury ,region1 ,connecticut4 ,hartford1 #aibj4 #ei pp41 #e pls41 #aj figs41 #be;cm4 ,state of ,connecticut ,,public ,,document ,no4 #dg ,state ,geological and ,natural ,history ,survey ,,herbert ,e4 ,,gregory1 ,,superintendent ,,bulletin ,no4 #cj ,hartford ,printed by the ,state ,geological and ,natural ,history ,survey #aibj ,state ,geological and ,natural ,history ,survey ,,commissioners ,marcus ,h4 ,holcomb1 ,governor of ,connecticut ,arthur ,twining ,hadley1 ,president of ,yale ,university ,william ,arnold ,shanklin1 ,president of ,wesleyan ,university ,remsen ,brickerhoff ,ogilby1 ,president of ,trinity ,college ,charles ,lewis ,beach1 ,president of ,connecticut ,agricultural ,college ,benjamin ,tinkham ,marshall1 ,president of ,connecticut ,college for ,women ,,superintendent ,herbert ,e4 ,gregory ,publication ,approved by the ,board of ,control ,drainage ,modifications and ,glaciation in the ,danbury ,region ,connecticut ,by ,,ruth ,,sawyer ,,harvey1 ,ph4 ,d4 ,,hartford ,printed by the ,state ,geological and ,natural ,history ,survey #aibj ,,contents4 ------ ,page ,introduction #i ,regional relations #aa ,rocky ,river #ae ,description of the river and its valley #ae ,relation of the valley to geologic structure #af ,junction of ,rocky and ,housatonic ,rivers #ah ,abnormal profile #ah ,preglacial course #bj ,the buried channel #bc ,effect of glaciation #be ,the ,neversink-,danbury valley #bg ,still ,river #cj ,statement of the problem #cj ,evidence to be expected if ,still ,river has been reversed #ca ,a valley wide throughout or broadening toward the south #cb ,tributary valleys pointing upstream #cd ,the regional slope not in accord with the course of the ,still #ce ,evidence of glacial filling and degrading of the river bed #cf ,glacial scouring #cf ,the ,still-,saugatuck divide #ch ,features of the ,umpog valley #ch ,the preglacial divide #db ,the ,still-,croton divide #dc ,introduction #dc ,features of ,still ,river valley west of ,danbury #dc ,the ,still-,croton valley #dd ,glacial ,lake ,kanosha #de ,divides in the highlands south of ,danbury #df ,the ancient ,still ,river #dg ,departures of ,still ,river from its preglacial channel #dh ,suggested courses of ,housatonic ,river #ej ,glacial deposits #ec ,beaver ,brook ,swamp #ec ,deposits northeast of ,danbury #ed ,deposits between ,beaver ,brook ,mountain and mouth of ,still ,river #ed ,lakes #ee ,history of the glacial deposits #ef ,,illustrations4 ----------- ,to ,face ,page ,,plate ,i ,view south on the ,highland northeast of ,neversink ,pond #ad ,,ii ,a4 ,view up the valley of ,umpog ,creek #dj ,b4 ,view down the valley of ,umpog ,creek #dj ,,iii ,limestone plain southwest of ,danbury1 in which are situated ,lake ,kanosha and the ,danbury ,fair ,grounds #dd ,,iv ,a4 ,view down the ,housatonic ,valley from a point one-half mile below ,stillriver ,station #eb ,b4 ,part of the morainal ridge north of ,danbury #eb ,v ,a4 ,kames in ,still ,river valley west of ,brookfield ,junction #ed ,b4 ,till ridges on the western border of ,still ,river valley1 south of ,brookfield #ef ,page ,,figure #a4 ,present drainage of the ,danbury region #ac #b4 ,geological map of ,still ,river valley #ag #c4 ,profiles of present and preglacial ,rocky ,river #ai #d4 ,preglacial course of ,rocky-,still ,river #ba #e4 ,diagram showing lowest rock levels in ,rocky ,river valley #bd #f4 ,course of ,still ,river #bi #g4 ,map of ,umpog ,swamp and vicinity #ci #h4 ,profiles of rivers #da #i4 ,early ,stage of ,rocky-,still ,river #di #aj4 ,five suggested outlets of ,housatonic ,river #ea ,,introduction ,the ,danbury region of ,connecticut presents many features of geographic and geologic interest4 ,it may be regarded as a type area1 for the history of its streams and the effects of glaciation are representative of those of the entire ,state4 ,with this idea in mind1 the field work on which this study is based included a traverse of each stream valley and an examination of minor features1 as well as a consideration of the broader regional problems4 ,much detailed and local description1 therefore1 is included in the text4 ,the matter in the present bulletin formed the main theme of a thesis on ,drainage and ,glaciation in the ,central ,housatonic ,basin which was submitted in partial fulfillment of the requirements for the degree of doctor of philosophy at ,yale ,university4 ,the field work was done in #aijg and #aijh under the direction of ,professor ,herbert ,e4 ,gregory4 ,i am also indebted to the late ,professor ,joseph ,barrell and to ,dr4 ,isaiah ,bowman for helpful cooperation in the preparation of the original thesis1 and to ,dr4 ,h4 ,h4 ,robinson for assistance in preparing this paper for publication4 ,,drainage ,,modifications ,,and ,,glaciation ,,in ,,the ,,danbury ,,region1 ,,connecticut -------- ,by ,ruth ,s4 ,harvey ,,regional ,,relations ,the region discussed in this bulletin is situated in western ,connecticut and is approximately #h miles wide and #ah miles long in a north-south direction1 as shown on fig4 #a4a ,throughout1 the rocks are crystalline and include gneiss1 schist1 and marble--the metamorphosed equivalents of a large variety of ancient sedimentary and igneous rocks4 ,for the purposes of this report1 the geologic history may be said to begin with the regional uplift which marked the close of the ,mesozoic4 ,by that time the mountains formed by ,triassic and ,jurassic folding and faulting had been worn down to a peneplain1 now much dissected but still recognizable in the accordant level of the mountain tops4 ,erosion during ,cretaceous time resulted in the construction of a piedmont plain extending from an undetermined line #cj to #ee miles north of the present ,connecticut shore to a point south of ,long ,island4#b ,this plain is thought to have been built up of unconsolidated sands1 clays1 and gravels1 the debris of the ,jurassic mountains4 ,inland the material consisted of river-made or land deposits2 outwardly it merged into coastal plain deposits4 ,when the plain was uplifted1 these loose gravels were swept away4 ,in ,new ,york1 ,pennsylvania1 and ,new ,jersey1 however1 portions of the ,cretaceous deposits are still to be found4 ,such deposits are present1 also1 on the north shore of ,long ,island1 and a well drilled at ,barren ,island on the south shore revealed not less than #ejj feet of ,cretaceous strata4#c ,the existence of such thick deposits within #cj miles of the ,connecticut shore and certain peculiarities in the drainage have led to the inference that the ,cretaceous cover extended over the southern part of ,connecticut4 ,footnote #a3 ,the streams and other topographic features of the ,danbury region are shown in detail on the ,danbury and the ,new ,milford sheets of the ,united ,states ,topographic ,atlas4 ,these sheets may be obtained from the ,director of the ,united ,states ,geological ,survey1 ,washington1 ,d4 ,c4 ,footnote #b3 ,it was probably not less than #cj miles1 for that is the distance from the mouth of ,still ,river1 where the ,housatonic enters a gorge in the crystallines1 to the sea4 ,fifty-five miles is the distance to the sea from the probable old head of ,housatonic ,river on ,wassaic ,creek1 near ,amenia1 ,new ,york4 ,footnote #c3 ,veatch1 ,a4 ,c41 ,slichter1 ,c4 ,s41 ,bowman1 ,isaiah1 ,crosby1 ,w4 ,o41 and ,horton4 ,r4 ,e41 ,underground water resources of ,long ,island3 ,u4 ,s4 ,g4 ,s41 ,,pp4 #dd1 p4 #ahh and fig4 #bd1 #aijf4 ,a general uplift of the region brought this period of deposition to a close4 ,as the peneplain1 probably with a mantle of ,cretaceous deposits1 was raised to its present elevation1 the larger streams kept pace with the uplift by incising their valleys4 ,the position of the smaller streams1 however1 was greatly modified in the development of the new drainage system stimulated by the uplift4 ,the modern drainage system may be assumed to have been at first consequent1 that is1 dependent for its direction on the slope of the uplifted plain1 but it was not long before the effect of geologic structure began to make itself felt4 ,in the time when all the region was near baselevel1 the harder rocks had no advantage over the softer ones1 and streams wandered where they pleased4 ,but after uplift1 the streams began to cut into the plain1 and those flowing over limestone or schist deepened1 then widened their valleys much faster than could the streams which flowed over the resistant granite and gneiss4 ,by a system of stream piracy and shifting1 similar to that which has taken place throughout the ,newer ,appalachians1 the smaller streams in time became well adjusted to the structure4 ,they are of the class called subsequents2 on the other hand1 the ,housatonic1 which dates at least from the beginning of the uplift if not from the earlier period of peneplanation1 is an antecedent stream4 ,the complex rock surface of western ,connecticut had reached a stage of mature dissection when the region was invaded by glaciers4#d ,the ice sheet scraped off and redistributed the mantle of decayed rock which covered the surface and in places gouged out the bedrock4 ,the resulting changes were of a minor order1 for the main features of the landscape and the principal drainage lines were the same in preglacial time as they are today4 ,it is thus seen that the history of the smaller streams like those considered in this report involves three factors3 7#a7 the normal tendencies of stream development1 7#b7 the influence of geologic structure1 and 7#c7 the effect of glaciation4 ,the cover of glacial deposits is generally thin1 but marked variations exist4 ,the fields are overspread with coarse till containing pebbles #f inches in diameter to huge boulders of #ab feet or more4 ,the abundance1 size1 and composition of the boulders in the till of a given locality is well represented by the stone fences which border fields4 ,footnote #d3 ,this stage of glaciation is presumably ,wisconsin4 ,no definite indication of any older glacial deposits was found4 ,illustration3 ,fig4 #a4 ,present drainage of the ,danbury region4 ,the regional depression which marked the close of the glacial period slackened the speed of many rivers and caused them to deposit great quantities of modified or assorted drift4 ,since glacial time1 these deposits have been dissected and formed into the terraces which are characteristic of the rivers of the region4 ,a form of terrace even more common than the river-made terrace is the kame terrace found along borders of the lowlands4 ,eskers in the ,danbury region have not the elongated snake-like form by which they are distinguished in some parts of the country1 notably ,maine2 on the contrary1 they are characteristically short and broad1 many having numerous branches at the southern end like the distributaries of an aggrading river4 ,the material of the eskers ranges from coarse sand to pebbles four inches in diameter1 the average size being from one to two inches4 ,no exposures were observed which showed a regular diminution in the coarseness of the material toward their southern end4 ,the clean-washed esker gravels afford little encouragement to plant growth1 and the rain water drains away rapidly through the porous gravel4 ,consequently1 accumulations of stratified drift are commonly barren places4 ,a desert vegetation of coarse grasses1 a kind of wiry moss1 and everlastings 7,gnaphalius decurrens7 are the principal growth4 ,rattlebox 7,crotolaria sagittalis71 steeplebush 7,spiraea tomentosa71 sweet fern 7,comptonia asplenifolia71 and on the more fertile eskers--especially on the lower1 wetter part of the slope--golden rod1 ox-eyed daisy1 birch1 and poplar are also present4 ,all the eskers observed were found to be similar3 they ranged in breadth across the top from #ajj to #aej feet and the side slopes were about #bj degrees4 ,only a single heavily wooded esker was found1 and this ran through a forest region4 ,the accumulations of stratified drift are distinguished from other features in the landscape by their smoother and rounder outlines1 by their habit of lying unconformably on the bedrock without reference to old erosion lines1 and by a slightly different tone in the color of the vegetation covering the water-laid material4 ,the difference in color1 which is due to the unique elements in the flora of these areas1 may cause a hill of stratified drift in summer to present a lighter green color than that of surrounding hills of boulder clay or of the original rock slopes2 in winter the piles of stratified drift stand out because of the uniform light tawny red of the dried grass4 ,illustration3 ,state ,geol4 ,nat4 ,hist4 ,survey ,bull4 #cj4 ,plate ,i4 ,view south on the highland northeast of ,neversink ,pond4 ,the base of a ridge in which rock is exposed is seen at the left2 a crescent-shaped lateral moraine bordering the valley lies at the right4 ,,rocky ,,river ,,description ,,of ,,the ,,river ,,and ,,its ,,valley ,rocky ,river begins its course as a rapid mountain brook in a rough highland1 where the mantle of till in many places is insufficient to conceal the rock ledges 7fig4 #a74 ,near ,sherman1 about four miles from its source1 it enters a broad flood plain and meanders over a flat1 swampy floor which is somewhat encumbered with deposits of stratified drift and till4 ,rocky hills border the valley and rise abruptly from the lowland4 ,the few tributaries of the river in this part of its course are normal in direction4 ,about six miles below ,sherman1 ,rocky ,river enters ,wood ,creek ,swamp1 which is #e-a_/b miles long by about one mile wide and completely covers the valley floor1 extending even into tributary valleys4 ,within the swamp the river is joined by ,squantz ,pond ,brook and ,wood ,creek4 ,tributaries to ,wood ,creek include ,mountain ,brook and the stream passing through ,barses ,pond and ,neversink ,pond4 ,the head of ,barses ,pond is separated from the swamp only by a low ridge of till4 ,neversink ,pond with its inlet gorge and its long southern tributary record significant drainage modifications1 as described in the section entitled ,the ,neversink-,danbury ,valley4 ,within and along the margin of ,wood ,creek ,swamp1 also east of ,wood ,creek and at ,barses ,pond1 are rounded1 elongated ridges of till1 some of which might be called drumlins4 ,east of ,neversink ,pond is the lateral moraine shown in ,pl4 ,i4 ,from the mouth of ,wood ,creek to ,jerusalem1 ,rocky ,river is a quiet stream wandering between low banks through flat meadows1 which are generally swampy almost to the foot of the bordering hills4 ,near ,jerusalem bridge two small branches enter ,rocky ,river4 ,immediately north of the bridge is a level swampy area about one-half mile in length4 ,where the valley closes in again1 bedrock is exposed near the stream1 and beginning at a point one-half mile below 7north of7 ,jerusalem1 ,rocky ,river--a swift torrent choked by boulders of great size--deserves its name4 ,in spite of its rapid current1 however1 the river is unable to move these boulders1 and for nearly three miles one can walk dry-shod on those that lie in midstream4 ,at two or three places below ,jerusalem1 in quiet reaches above rapids1 the river has taken its first step toward making a flood plain by building tiny beaches4 ,one-half mile above the mouth of the river the valley widens and on the gently rising south bank there are several well-marked terraces about three feet in height and shaped out of glacial material4 ,a delta and group of small islands at the mouth of ,rocky ,river indicate the transporting power of the stream and the relative weakness of the slow-moving ,housatonic4 ,,relations ,,of ,,the ,,valley ,,to ,,geologic ,,structure ,rocky ,river is classed with streams which are comformable to the rock structure4 ,this conclusion rests largely on the analogy between ,rocky ,river and other rivers of this region4 ,the latter very commonly are located on belts of limestone1 or limestone and schist1 and their extension is along the strike4 ,the interfluvial ridges are generally composed of the harder rocks4 ,the valleys of the ,east ,aspetuck and ,womenshenuck ,brook on the north side of the ,housatonic1 and of the ,still1 the ,umpog1 ,beaver ,brook1 the upper ,saugatuck1 and part of ,rocky ,river are on limestone beds 7fig4 #b74 ,in the valleys between ,town ,hill and ,spruce ,mountain 7south of ,danbury71 two ravines northwest of ,grassy ,plain 7near ,bethel71 and the ,saugatuck valley north of ,umpawaug ,pond1 the limestone bed is largely buried under drift1 talus1 and organic deposits1 but remnants which reveal the character of the valley floors have been found4 ,the parallelism between the courses of these streams and that of ,rocky ,river and the general resemblance in the form of their valleys1 flat-floored with steep-sided walls1 as well as the scattered outcrops of limestone in the valley1 have led to the inference that ,rocky ,river1 like the others1 is a subsequent stream developed on beds of weaker rock along lines of foliation4 ,illustration3 ,fig4 #b4 ,geological map of ,still ,river ,valley4 ,the ,geological ,map of ,connecticut#e shows that the valleys of ,still ,river1 ,womenshenuck ,brook1 ,aspetuck ,river1 and upper ,rocky ,river are developed on ,stockbridge limestone4 ,the lower valley of ,rocky ,river is1 however1 mapped as ,becket gneiss and ,thomaston granite gneiss4 ,although the only outcrops along lower ,rocky ,river are of granite1 it is believed that a belt of limestone or schist1 now entirely removed1 initially determined the course of the river4 ,the assumption of an irregular belt of limestone in this position would account for the series of gorges and flood plains in the vicinity of ,jerusalem bridge and for the broad drift-filled valley at the mouth of ,rocky ,river4 ,these features are difficult to explain on any other basis4 ,footnote #e3 ,gregory1 ,h4 ,e41 ,robinson1 ,h4 ,h41 ,preliminary geological map of ,connecticut2 ,geol4 and ,nat4 ,hist4 ,survey4 ,bull4 #g1 #aijg4 ,,junction ,,of ,,rocky ,,and ,,housatonic ,,rivers ,one of the distinguishing features of ,rocky ,river is the angle at which it joins the ,housatonic 7fig4 #a74 ,the tributaries of a normal drainage system enter their master stream at acute angles1 an arrangement which involves the least expenditure of energy4 ,rocky ,river1 however1 enters the ,housatonic against the course of the latter1 that is1 the tributary points upstream4 ,still ,river and other southern tributaries of the ,housatonic exhibit the same feature1 thus producing a barbed drainage1 which indicates that some factor interfered with the normal development of tributary streams4 ,barbed drainage generally results from the reversal of direction of the master stream#f1 but it is impossible to suppose that the ,housatonic was ever reversed4 ,as will appear1 it is an antecedent master stream crossing the crystalline rocks of western ,connecticut regardless of structure1 and its course obliquely across the strike accounts for the peculiar orientation of its southern tributaries1 which are subsequent streams whose position is determined by the nature of the rock4 ,for the same reason1 the northern tributaries of the ,housatonic present the usual relations4 ,footnote #f3 ,leverett1 ,frank1 ,glacial formations and drainage features of the ,erie and ,ohio basins3 ,u4 ,s4 ,geol4 ,survey ,mon4 #da1 pp4 #hh-ia1 figs4 #a and #b1 #aijb4 ,see1 also1 the ,genoa1 ,watkins1 ,penn ,yan1 and ,naples 7,new ,york7 topographic atlas sheets4 ,,abnormal ,,profile ,the airline distance from the bend in ,rocky ,river at ,sherman to its mouth at the ,housatonic is #b-c_/d miles1 but the course of the river between these two points is #ae miles1 or #e4d times the airline distance4 ,this is a more extraordinary digression than that of ,tennessee ,river1 which deserts its ancestral course to the ,gulf and flows northwest into the ,ohio1 multiplying the length of its course #c-a_/c times4 ,the fall of ,rocky ,river between ,sherman and its mouth is #bdj feet or #af feet to the mile1 and were the river able to take a direct course the fall would be #hg feet to the mile4 ,the possibility of capture would seem to be imminent from these figures1 but in reality there is no chance of it1 for an unbroken mountain ridge of resistant rock lies between the two forks of the river4 ,this barrier is not likely to be crossed by any stream until the whole region has been reduced to a peneplain4 ,measured from the head of its longest branch1 ,rocky ,river is about #ai miles long and falls #iej feet4 ,of this fall1 #gaj feet occurs in the first #d miles and #agc feet in the last #b-a_/b miles of its course4 ,for the remaining distance of #ab-a_/b miles1 in which the river after flowing south doubles back on itself1 the fall is #fg feet1 or slightly less than #e-a_/b feet to the mile 7fig4 #c1 ,a74 ,illustration3 ,fig4 #c4 ,profiles of present and preglacial ,rocky ,river4 ,elevations at a1 b1 c and i are from ,u4 ,s4 ,g4 ,s4 map4 ,elevation at d is estimated from ,r4 ,e4 ,dakin's records4 ,elevations at e1 f1 g and h are from ,r4 ,e4 ,dakin's records4 ,the ,u4 ,s4 ,g4 ,s4 figures for the same are enclosed in parenthesis4 ,in tabular form the figures1 taken from the ,danbury and ,new ,milford atlas sheets and from reports of ,r4 ,e4 ,dakin1 are as follows3 ,miles ,fall in feet per mile ,source to ,sherman #d #agg4e ,sherman to ,wood ,creek #h #f4be ,wood ,creek to ,jerusalem #d4e #c4h ,jerusalem to mouth #b4e #fi4b ,near ,jerusalem1 where ,rocky ,river makes its sudden change in grade1 there is an abrupt change in the form of the valley from broad and flat-bottomed to narrow and ,v-shaped4 ,the profile of ,rocky ,river is thus seen to be sharply contrasted with that of a normal stream1 which is characterised throughout its course by a decreasing slope4 ,,preglacial ,,course ,the present profile of ,rocky ,river and the singular manner in which the lower course of the river is doubled back on the upper course are believed to represent changes wrought by glaciation4 ,before the advent of the glacier1 ,rocky ,river probably flowed southward through the ,neversink-,danbury ,valley1 to be described later1 and joined the ,still at ,danbury1 as shown in fig4 #d4 ,the profile of the stream at this stage in its history is shown in fig4 #c1 ,b4 ,at ,sherman a low col separates ,rocky ,river basin from that of the small northward flowing stream which enters the ,housatonic about a mile below ,gaylordsville4 ,streams by headward erosion at both ends of the belt of limestone and schist on which they are situated have reduced this divide to an almost imperceptible swell4 ,the rock outcrops in the channel show that the glacier did not produce any change in the divide by damming1 though it may have lowered it by scouring4 ,assume that at one time a divide also existed on the eastern fork of ,rocky ,river1 for example near ,jerusalem4 ,according to this hypothesis there was1 north of this latter divide1 a short northward flowing branch of the ,housatonic located on a belt of weak rock1 similar to the small stream which now flows northward from ,sherman1 and very like any of the half-dozen parallel streams in the rock mass south and southwest of ,danbury1 all of which are subsequent streams flowing along the strike4 ,while these stream valleys were growing1 the southern ends of the same weak belts of rock were held by southward-flowing streams which united in the broad limestone area now occupied by the city of ,danbury4 ,illustration3 ,fig4 #d4 ,preglacial course of ,rocky-,still ,river4 ,dotted lines show present courses of the two rivers4 ,the southward-flowing streams whose heads were1 respectively1 above ,sherman and near ,jerusalem joined at the southern end of the long ridge which includes ,towner ,hill and ,green ,mountain4 ,thence the stream flowed southward along the valley now occupied by ,wood ,creek and reached ,still ,river by way of the valley which extends southward from ,neversink ,pond 7fig4 #d74 ,the preglacial course of ,rocky ,river1 as above outlined1 is subject to possible modification in one minor feature1 namely1 the point where the east and west forks joined4 ,the junction may have been where ,neversink ,pond is now situated1 or three miles farther south than the indicated junction near the mouth of ,wood ,creek4 ,a low ridge of till is the only barrier that at present prevents the western branch from flowing into the head of ,barses ,pond and thence into ,neversink ,pond 7fig4 #a74 ,as thus reconstructed the greater part of ,rocky ,river formerly belonged to the ,still-,umpog system and formed a normal tributary in that distant period when the ,still joined the ,saugatuck on its way to the ,sound 7fig4 #i74 ,however1 the normal condition was not lasting1 for the reversal of ,still ,river1 as later described1 brought about a complex arrangement of barbed streams 7fig4 #d7 which remained until modified by glacial action4 ,in a large stream system which has been reversed1 considerable evidence may be gathered from the angle at which tributary streams enter4 ,as the original direction of ,rocky ,river in its last #b-a_/b miles is unchanged1 normal tributaries should be expected2 whereas between ,jerusalem and the head of the stream entering ,neversink ,pond from the south1 in accordance with the hypothesis that this portion of the stream was reversed1 tributaries pointing upstream might be expected4 ,such little gullies as join ,rocky ,river near its mouth are normal in direction2 between ,jerusalem and the mouth of ,wood ,creek1 a distance of #d-a_/b miles1 there are no distinct tributaries4 ,south of the mouth of ,wood ,creek are four tributaries3 7#a7 the brook which enters the valley from the west about one mile south of ,neversink ,pond1 7#b7 ,balls ,brook1 which empties into ,neversink ,pond1 and 7#c7 two streams on the east side--,mountain ,brook and one other unnamed 7fig4 #a74 ,all these1 except ,mountain ,brook1 are normal to the reconstructed drainage4 ,the evidence of the tributaries1 though not decisive1 is thus favorable to the hypothesis of reversal4 ,,the ,,buried ,,channel ,figures #c and #e show what is known of the buried channel of ,rocky ,river4 ,the only definite information as to rock levels is that derived from the drill holes made by ,r4 ,e4 ,dakin for the ,j4 ,a4 ,p4 ,crisfield ,contracting ,company in connection with work on a reservoir for the ,connecticut ,light and ,power ,company4 ,numerous holes were drilled at the points indicated on fig4 #e as ,no4 #h1 ,d1 ,j1 ,no4 #gajjj1 and ,no4 #g1 but only those showing the lowest rock levels need be considered4 ,in the following account the elevations quoted are those determined by ,r4 ,e4 ,dakin which differ1 as shown in fig4 #c1 ,a1 from those of the ,new ,milford atlas sheet4 ,between the mouth of ,wood ,creek and ,jerusalem bridge holes made near the river show that the depth of the drift--chiefly sand1 gravel1 and clay--varies from #de to #adj feet4 ,the greatest thickness of drift1 consisting of humus1 quicksand and clay1 is #adj feet at a point #bj feet from the east bank of ,rocky ,river and about #a-c_/d miles north of the mouth of ,wood ,creek 7fig4 #e1 ,d74 ,although some allowance should be made for glacial scouring1 the rock level at this point1 #bdd feet1 is so much lower than any other record obtained between this point and ,danbury that one is obliged to assume a buried channel with a level at ,danbury at least #ge feet below the rock level found in the lowest well record4#g ,it is probable that this well is not situated where the rock is lowest1 that is1 it may be on one side of the old ,still ,river channel4 ,footnote #g3 ,well of ,j4 ,hornig1 rear of ,bottling ,works1 near foot of ,tower ,place1 #ce ft4 to rock1 indicated at a1 fig4 #e4 ,the well of ,bartley ,clancey1 #id ,white ,street1 #gj ft4 to rock1 is also indicated at b1 fig4 #e4 ,the level obtained at ,no4 #h is from a hole drilled within #ej feet of the river4 ,the drill struck rock at an elevation of #caf feet after passing through #fi feet of quicksand1 gravel1 and till4 ,this is clearly not within the channel as it is quite impossible to reconcile the figure with that at ,d1 less than a mile distant4 ,south of ,jerusalem bridge at ,j1 #aej feet from the river1 a hole was bored through #ie feet of clay1 sand1 and gravel before striking rock at an elevation of #bih feet4 ,illustration3 ,fig4 #e4 ,rocky ,river ,valley4 ,diagram indicating lowest rock levels which have been discovered by drilling4 ,at the point marked ,no4 #gajjj1 about #a-a_/d miles from the mouth of ,rocky ,river1 the evidence derived from #h drill holes1 bored at distances ranging from #bjj to #eej feet from the right bank1 shows the drift cover to be from #dh to #gb feet in thickness4 ,at #bjj feet from the river the drill passed through #gb feet of sand1 clay1 and gravel before striking rock at #cjc feet above sea-level4 ,at ,no4 #g1 about one mile from the mouth of ,rocky ,river1 a hole drilled #dae feet from the right bank showed #eh feet of drift1 consisting of clay1 sand1 gravel1 and boulders4 ,the drill reached rock at #cdb feet1 which is the figure given by ,r4 ,e4 ,dakin for the elevation of the river at this point4 ,drill holes made1 respectively1 at #ej and #fj feet to the right of this one showed a drift cover of #fa feet1 so that the underlying rock rises only #d feet in a distance of #dge feet to the east of the river4 ,the foregoing evidence1 showing a rock level at ,d #ih feet lower than that at ,no4 #g1 leaves no doubt that the preglacial course of ,rocky ,river was to the south from ,no4 #g1 and there is nothing in the topography between ,jerusalem and ,danbury to make improbable the existence of a buried channel4 ,,effect ,,of ,,glaciation ,the preglacial history of ,rocky ,river as outlined assumes that before the glacier covered this part of ,connecticut the present lower course of ,rocky ,river was separated from the rest of the system by a divide situated somewhere between the present mouth of the river and the mouth of ,wood ,creek4 ,it remains to be shown by what process ,rocky ,river was cut off from its southern outlet into ,still ,river and forced up its eastern branch and over the col into a tributary of the ,housatonic4 ,though the preglacial course of ,rocky ,river appears to be more natural than the present one1 it is really a longer course to the ,housatonic2 the older route being #cb miles1 whereas the present course is #ai miles4 ,this fact explains1 in part1 why the glacier had little difficulty in altering the preglacial drainage1 and how the change so effected became permanent4 ,eccentric as the resulting system of drainage is1 it would have been still more so had ,rocky ,river when ponded overflowed at the head of its western instead of its eastern fork1 taken its way past ,sherman into the ,housatonic near ,gaylordsville1 and discharging at this point lost the advantage of the fall of the ,housatonic between ,gaylordsville and ,boardman4 ,in glaciated regions an area of swamp land may be taken as an indication of interference by the glacier with the natural run-off4 ,the swamp in which ,wood ,creek joins the upper fork of ,rocky ,river 7fig4 #a71 was formerly a lake due to a dam built across the lower end of a river valley4 ,although the ponded water extended only a short distance up the steeper side valleys1 it extended several miles up the main stream4 ,the whole area of this glacial lake1 except two small ponds and the narrow channels through which the river now flows1 has been converted into a peat-filled bog having a depth of from #h to #de feet4#h ,at the termination of the swampy area on the eastern branch of ,rocky ,river no indication is found of a dam such as would be required for so extensive a ponding of the waters4 ,here the valley is very narrow1 and though the river bed is encumbered with heavy boulders1 rock outcrops are so numerous as to preclude the idea of a drift cover raising the water level4 ,this is just the condition to be expected if ,rocky ,river reached its present outlet by overtopping a low col at the head of its former eastern branch4 ,the southern end of the ,neversink ,pond valley is the only other place whose level is so low that drift deposits could have interfered with the ,rocky ,river drainage4 ,the moraine at the head of this valley1 crossing the country some two miles north of the city of ,danbury and binding together two prominent north-and-south ridges1 was evidently the barrier which choked the ,rocky ,river valley near its mouth and turned back the preglacial river4 ,when ,rocky ,river was thus ponded its lowest outlet was found to be at the head of its eastern fork4 ,here the waters spilled over the old divide and took possession of the channel of a small stream draining into the ,housatonic4 ,accordingly ,rocky ,river should be found cutting its bed where it crosses the former divide4 ,it seems reasonable to regard the gorge half-way between ,jerusalem bridge and ,housatonic ,river as approximately the position of the preglacial divide and to consider the small flat area to the north of ,jerusalem bridge as a flood plain on softer rock1 worn down as low as the outcrops of more resistant rock occurring farther down the valley will permit4 ,the reversal of the river may account for the sudden transition from a flat-bottomed valley to a rocky gorge2 and for the abrupt change in the profile1 bringing the steepest part of the river near its mouth4 ,the increased volume of water flowing through the channel since glacial time has plainly cut down the bed of the ravine between ,jerusalem and the river's mouth1 but the channel is still far from being graded4 ,footnote #h3 ,report of soundings made in #aijg by ,t4 ,t4 ,giffen4 ,,the ,,neversink-,,danbury ,,valley4 ,between ,neversink ,pond and ,danbury extends a deep rock valley1 in places filled with drift4 ,as has been shown1 this valley was probably occupied in preglacial time by ,rocky ,river1 which then flowed southward4 ,at its southern end is ,still ,river1 which flows through ,danbury from west to east4 ,the most important tributary of the ,still rises northwest of the city1 just beyond the ,new ,york-,connecticut boundary line1 and has two forks4 ,the northern fork1 which drains ,east ,lake1 ,padanaram ,reservoir1 and ,margerie ,pond1 flows along the northeast side of ,clapboard ,ridge4 ,the southern fork has two branches2 the northern one includes the reservoirs of ,upper ,kohanza and ,lake ,kohanza1 while the upper waters of the southern branch have been recently dammed to form an extensive reservoir4 ,on approaching the city1 the northernmost fork 7draining ,east ,lake7 turns sharply out of its southeast course and flows in a direction a little east of north4 ,at the end of ,clapboard ,ridge1 the stream makes a detour around a knoll of coarse stratified drift4 ,from this turn until it joins ,still ,river1 a distance of about a mile1 the stream occupies a broad and partly swampy valley4 ,at the cemetery in this valley 7fig4 #a1 ,c7 are two eskers of symmetric form1 each a few hundred yards in length and trending nearly parallel with the valley axis4 ,east of the valley1 and about #a-a_/b miles north of the cemetery1 is a broad1 flat-topped ridge of till with rock exposed at the ends1 forming a barrier which doubtless existed in preglacial time4 ,west of the valley is a hill with rock foundation rounded out on the northeast side by a mass of drift4 ,the preglacial course of ,rocky ,river was between the outcrops at these two localities4 ,northwest of the cemetery for one and a half miles the uneven surface is formed of till and small patches of stratified drift4 ,in a swamp near the north end of the cemetery is a curved esker with lobes extending south and southwest4 ,one mile north of this swamp is an area of excessively coarse till containing boulders which range in diameter from #f to #aj feet and forming a low ridge separating two ravines1 in which head streams flowing in opposite directions4 ,the area of coarse till is bounded on the north by a long sinuous esker of coarse gravel terminating in a flat fan1 which is superposed on a field of fine till4 ,associated with the esker is an interesting group of kames and kettleholes1 the largest kettlehole being distinguished by distinct plant zones banding the sides of the depression4 ,north of the area of boulders1 eskers1 and kames just described lies a swamp whose surface is #cj to #dj feet below the upper level of the kame gravels4 ,soundings made by ,t4 ,t4 ,giffen revealed the presence of #cf feet of peat and #b feet of silt overlying firm sand1 so that #gj feet is the minimum estimate for the difference in level between the surface of the gravels and the floor of the swamp4 ,below the rocky cliffs which line the valley sides are boulders brought by the ice from near-by ledges1 and about one-half mile above the head of the swamp are remnants of a terrace standing #bj to #cj feet above the level of the stream4 ,although the terrace appears to consist of till1 it may conceal a rock floor which was cut by a former stream4 ,as the valley is followed toward ,neversink ,pond1 the various features of a till-coated1 rock-floored valley are seen4 ,illustration3 ,fig4 #f4 ,course of ,still ,river4 ,dotted lines show the preglacial channels4 ,,still ,,river ,,statement ,,of ,,the ,,problem ,still ,river presents several unusual features1 as shown in fig4 #f4 ,tributaries from the west and south unite at ,danbury to form a stream flowing northward opposite to the regional land slope4 ,near its junction with the ,housatonic1 the river flows northward1 whereas its master stream half a mile distant flows southward4 ,the lower valley of the river is broad and flat and apparently much out of proportion to the present stream2 it is1 indeed1 comformable in size and direction with the valley of the ,housatonic above the mouth of the ,still4 ,the ,housatonic1 however1 instead of choosing the broad lowland in the limestone formation1 spread invitingly before it1 turns aside and flows through a narrow gorge cut in resistant gneiss1 schist1 and igneous intrusives4 ,the headwaters of the ,still mingle with those of the ,croton system1 and its chief southern branch1 the ,umpog1 is interlaced with the sources of the ,saugatuck on a divide marked by glacial drift and swamps4 ,the explanation of these features involves not only the history of the ,still ,river system1 but also that of the ,housatonic4 ,in explanation of the present unusual arrangement of streams in the ,still ,river system1 four hypotheses may be considered3 ,i4 ,still ,river valley is the ancient bed of the ,housatonic from which that river has been diverted through reversal caused by a glacial dam4 ,,ii4 ,the ,housatonic has always had its present southeasterly course1 but the ,still1 heading at some point in its valley north of ,danbury1 flowed initially southward through one of four possible outlets4 ,the latter stream was later reversed by a glacial dam at the southern end1 or by glacial scouring at the northern end of its valley which removed the divide between its headwaters and the ,housatonic4 ,,iii4 ,the ,housatonic has always held its present southeasterly course1 and the ,still initially flowed southward1 as stated above4 ,reversal in this case1 however1 occurred in a very early stage in the development of the drainage1 as the result of the capture of the headwaters of the ,still by a small tributary of the ,housatonic4 ,,iv4 ,the ,housatonic has always held its present southeasterly course1 but the ,still has developed from the beginning as a subsequent stream in the direction in which it now flows4 ,the first hypothesis1 that the ,still is the ancient channel of the ,housatonic1 has been advocated by ,professor ,hobbs1 who has stated3 ,that the valley of the ,still was formerly occupied by a large stream is probable from its wide valley area4444 ,the former discharge of the waters of the ,housatonic through the ,still into the ,croton system1 on the one hand1 or into the ,saugatuck on the other1 would require the assumption of extremely slight changes only in the rock channels which now connect them4444 ,to turn the river 7the ,housatonic7 from its course along the limestone valley some obstruction or differential uplift within the river basin may have been responsible4 ,the former seems to be the more probable explanation in view of the large accumulations of drift material in the area south and west of ,bethel and ,danbury4 ,the structural valleys believed to be present in the crystalline rocks of the uplands due to post-,newark deformation may well have directed the course of the ,housatonic after it had once deserted the limestone 444 ,the deep gorge of the ,housatonic through which the river enters the uplands not only crosses the first high ridge of gneiss in the rectilinear direction of one of the fault series1 but its precipitous walls show the presence of minor planes of dislocation1 along which the bottom of the valley appears to have been depressed4#i ,the hypothesis proposed by ,professor ,hobbs and also the second and third hypotheses here given involve the supposition of reversal of drainage1 and their validity rests on the probability that the stream now occupying ,still ,river valley formerly flowed southward4 ,the first and second hypotheses will be considered in the following section4 ,footnote #i3 ,hobbs1 ,w4 ,h41 ,still rivers of western ,connecticut3 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ac1 pp4 #ag-bf1 #aija4 ,,evidence ,,to ,,be ,,expected ,,if ,,still ,,river ,,has ,,been ,,reversed ,if ,still ,river occupies the valley of a reversed stream1 the following physiographic features should be expected3 #a4 ,a valley with a continuous width corresponding to the size of the ancient stream1 or a valley comparatively narrow at the north and broadening toward the south4 #b4 ,tributary valleys pointing upstream with respect to the present river4 #c4 ,the regional slope not in accord with the present course of the river4 #d4 ,extensive glacial filling and ponded waters in the region of the present sources of ,still ,river4 #e4 ,strong glacial scouring at the northern end in default of a glacial dam at the southern end of the valley1 or to assist a dam in its work of reversing the river4 ,the evidence of glacial erosion would be a ,u-shaped valley1 overdeepening of the main valley1 and tributaries ungraded with respect to the main stream4 #a4 ,a ,,valley ,,wide ,,throughout ,,or ,,broadening ,,toward ,,the ,,south ,at the mouth of ,still ,river and for several miles north and south of it there is a plain more than a mile broad4 ,this plain continues southward with a width of about one-half mile until1 at ,brookfield1 it is interrupted by ledges of bare rock4 ,a little distance south of ,brookfield the valley broadens again to one-half mile1 and this width is retained with some variation as far as ,danbury4 ,drift deposits along the border of the valley make it appear narrower in some places than is indicated by rock outcrops4 ,between ,brookfield and ,danbury the narrowest place in the valley is southwest of ,beaver ,brook ,mountain1 where the distance between the hills of rock bounding the valley is one-fifth of a mile 7fig4 #f74 ,opposite ,beaver ,brook ,mountain1 which presents vertical faces of granite-gneiss toward the valley1 is a hill of limestone4 ,ice1 crowding through this narrow place in the valley1 must have torn masses of rock from the side walls1 so that the valley is now broader than in preglacial time4 ,the constrictions in the valley near ,shelter ,rock are due to the fact that the preglacial valley1 now partly buried in till1 lies to the north4 ,there are stretches of broad floor in the valley of ,beaver ,brook1 in the lower valley of ,umpog ,creek1 in the fields at the south end of ,main ,street in ,danbury1 about ,lake ,kanosha1 and where the ,danbury ,fair ,grounds are situated4 ,in the western part of ,danbury1 however1 and at ,mill ,plain the valley is very narrow1 and at the head of ,sugar ,hollow1 the valley lying east of ,spruce ,mountain1 is a narrow col4 ,the broadest continuous area in the ,still-,umpog ,valley is1 therefore1 in the lower six miles between ,brookfield and ,new ,milford2 south of that portion are several places where the valley is sharply constricted2 and beyond the head of the ,umpog1 about one and a half miles below ,west ,redding station 7fig4 #g71 the ,saugatuck ,valley is a very narrow gorge4 ,on the whole1 the valleys south and southwest of ,danbury are much narrower than the valley of the ,still farther north4 ,it is evident from these observations that ,still ,river ,valley is neither uniformly broad1 nor does it increase in width toward the south4 ,but if a broad valley is to be accepted as evidence of the work of a large river1 then there is too much evidence in the ,still ,river valley4 ,the broad areas named above are more or less isolated lowlands1 some of them quite out of the main line of drainage1 and can not be grouped to form a continuous valley4 ,they can not be attributed to the ,housatonic nor wholly to the work of the insignificant streams now draining them4 ,these broad expanses are1 in fact1 local peneplains developed on areas of soluble limestone4 ,the rock has dissolved and the plain so produced has been made more nearly level by a coating of peat and glacial sand4 ,in a region of level and undisturbed strata1 such as the ,ohio or ,mississippi ,valley1 a constant relation may exist between the size of a stream and the valley made by it2 but in a region of complicated geologic structure1 such as western ,connecticut1 where rocks differ widely in their resistance to erosion1 the same result is not to be expected4 ,in this region the valleys are commonly developed on limestone and their width is closely controlled by the width of the belt of limestone4 ,even the narrow valleys in the upland southwest of ,danbury are to be accounted for by the presence of thin lenses of limestone embedded in gneiss and schist4 ,the opinion of ,hobbs that ,still ,river valley is too wide to be the work of the present stream takes into consideration only the broad places1 but when the narrow places are considered it may be said as well that the valley is too narrow to be the work of a stream larger than the one now occupying it4 ,valley width has only negative value in interpreting the history of ,still ,river4 #b4 ,,tributary ,,valleys ,,pointing ,,upstream ,the dominant topographic feature of western ,connecticut1 as may be seen on the atlas sheets1 is elongated oval hills trending north by west to south by east1 which is the direction of the axes of the folds into which the strata were thrown at the time their metamorphism took place4 ,furthermore1 the direction of glacial movement in this part of ,new ,england was almost precisely that of foliation1 and scouring by ice merely accentuated the dominant north-south trend of the valleys and ridges4 ,as a result1 the smaller streams developed on the softer rocks are generally parallel to each other and to the strike of the rocks4 ,these streams commonly bend around the ends of the hills but do not cross them4 ,the narrowness of the belts of soft rock makes it easy for the drainage of the valleys to be gathered by a single lengthwise stream4 ,the ,still and its larger tributaries conform in this way to the structure4 ,on the east side of the ,still-,umpog every branch1 except two rivulets #a-a_/d miles south of ,bethel1 points in the normal direction1 that is1 to the north1 or downstream as the river now flows 7fig4 #f74 ,the largest eastern tributary1 ,beaver ,brook1 is in a preglacial valley now converted into a swamp the location and size of which are due entirely to a belt of limestone4 ,it is not impossible that ,beaver ,brook may have once flowed southward toward ,bethel1 but the limestone at its mouth1 which lies at least #fj feet lower than that at its head1 shows that if such were ever the case it must have been before the north-flowing ,still ,river had removed the limestone north of ,beaver ,brook ,swamp4 ,on the flanks of ,beaver ,brook ,mountain are three tributaries which enter the river against its present course4 ,examination of the structure reveals1 however1 that these streams like those on the east side of the river are controlled in their direction by the orientation of the harder rock masses4 ,the southward flowing stream four miles in length which drains the upland west of ,beaver ,brook ,mountain has an abnormal direction in the upper part of its course1 but on reaching the flood plain it takes a sharp turn to the north4 ,above the latter point it is in line with the streams near ,beaver ,brook ,mountain and is abnormal in consequence of a line of weakness in the rock4 ,the lowland lying west of ,umpog valley1 extending from ,main ,street in ,danbury to a point one mile beyond ,bethel1 affords no definite evidence in regard to the direction of tributaries4 ,in reconstructing the history of this valley the chief difficulty arises from the old-age condition of the flood plain4 ,drainage channels which must once have existed have been obliterated1 leaving a swampy plain which from end to end varies less than #bj feet in elevation4 ,it is likely that in preglacial times the part of the valley north of ,grassy ,plain1 if not the entire valley1 drained northward into ,still ,river1 as now do ,umpog ,creek and ,beaver ,brook4 ,from this outlet heavy drift deposits near the river later cut it off4 ,the lowland is now drained by a stream which enters the ,umpog north of ,grassy ,plain4 ,several small streams tributary to the ,umpog south of ,bethel also furnish no evidence in favor of the reversal of ,still ,river4 ,west of ,danbury the tributaries of ,still ,river point upstream on one side and downstream on the other side of the valley1 in conformity with the rock structure which is here diagonal to the limestone belt on which the river is located4 ,their direction in harmony with the trend of the rocks has1 therefore1 no significance in the earlier history of the river4 ,from the foregoing discussion1 it appears that no definite conclusions in regard to the history of ,still ,river can be drawn from the angle at which tributaries enter it4 ,the direction of the branches which enter at an abnormal angle can be explained without assuming a reversal of the main stream1 and likewise many of the tributaries with normal trends seem to have adopted their courses without regard to the direction of ,still ,river4 #c4 ,,regional ,,slope ,,not ,,in ,,accord ,,with ,,course ,,of ,,the ,,still ,although the regional slope of western ,connecticut as a whole is contrary to that of ,still ,river1 there is no marked lowering of the hill summits between the source of the river and its mouth4 ,as branches on the south side of the ,housatonic are naturally to be expected1 there is nothing unusual in the ,still flowing in opposition to the regional slope1 except that it flows toward the north instead of the northeast4 #d4 ,,evidence ,,of ,,glacial ,,filling ,,and ,,degrading ,,of ,,the ,,river ,,bed ,hobbs has suggested that the waters of the ,housatonic may have been ponded at a point near ,west ,redding until they rose high enough to overflow into the fault gorge below ,still ,river ,station1 thus giving the streams of the ,danbury region an outlet to the ,sound by this route4 ,this hypothesis calls for a glacial dam which has not been found4 ,it is true there are glacial deposits in the ,umpog valley south of ,bethel4 ,the ,umpog flows as it does1 however1 not because of a glacial dam but in spite of it4 ,the river heads on rock beyond and above the glacial deposits and picks its way through them 7fig4 #g74 ,drift forms the divide at the western end of ,still ,river valley beyond ,mill ,plain1 but the ponded water which it caused did not extend as far as ,danbury 7see discussion of ,still-,croton valley74 ,the ,sugar ,hollow pass is also filled with a heavy mantle of drift1 but the valley is both too high and too narrow at the col to have been the outlet of the ,housatonic4 ,it might be assumed that just previous to the advent of the ice sheet ,still ,river headed south of its present mouth and flowed southward4 ,in this case the ,still1 when reversed1 should have overflowed at the lowest point on the divide between it and the ,housatonic4 ,it should have deepened its channel over the former divide1 and the result would have been a gorge if the divide were high1 or at least some evidence of river cutting even if the divide were low4 ,on the contrary1 ,still ,river joins the ,housatonic in a low1 broad1 and poorly drained plain4 ,the existing relief is due to the uneven distribution of drift4 ,the river is now cutting a gorge at ,lanesville1 but the appearance of the valley to the west indicates that glacial deposits forced the river out of its former bed 7fig4 #f7 and that no barrier lay between the preglacial ,still ,river valley and the ,housatonic ,valley4 #e4 ,,glacial ,,scouring ,a reversal of ,still ,river may be explained by glacial scouring which caused the northern end of the valley to become lower than the present divides at ,west ,redding and ,mill ,plain4 ,the evidence of such scour should be an overdeepened1 ,u-shaped main valley and ungraded tributaries4 ,the northern part of ,still ,river valley has not the typical ,u form which results from glacial erosion4 ,as contrasted with the ,u-shaped glacial valley and the ,v-shaped valley of normal stream erosion1 it might be called rectangular so sharply does the flat valley floor terminate against the steep hillsides4 ,the floor is too smooth and flat and the tributary valleys too closely adjusted to the variant hardness of the rocks to be the work of such a rough instrument as the glacier4 ,a level so nearly perfect as that of the flood plain is the natural result of erosion of soft rock down to a baselevel1 whereas glacial scouring tends to produce a surface with low rounded hills and hollows4 ,overdeepening would be expected1 because glaciers erode without reference to existing baselevels4 ,that a river valley should be cut out by ice just enough to leave it graded with respect to the main valley would be an unusual coincidence4 ,this is what is found where the ,still ,river valley joins the ,housatonic1 and it indicates normal stream erosion4 ,also1 if the limestone of the northern ,still ,river valley were gouged out by the glacier1 the action would in all probability have been continuous in the limestone belt to the north of the ,housatonic1 and where the belt of soft rock crosses the ,housatonic the river bed would be overdeepened4 ,although the valley of the ,housatonic near ,new ,milford is very flat1 as is natural where a river crosses a belt of weak rock1 the outcrops are sufficiently numerous to show that it has not been overdeepened4 ,the limestone area along the ,east ,aspetuck is largely overlain by till1 but here again the presence of rock in place shows that the valley has not been overdeepened4 ,moreover1 limestone boulders in the southern part of ,still ,river valley are not as abundant as they should be under the hypothesis that the northern part had been gouged out extensively4 ,that the northern part of the ,still ,river valley was not deeply carved by ice is shown also by the character of the tributary streams4 ,the three small brooks on the west side of the valley1 near ,beaver ,brook ,mountain1 were examined to see if their grades indicated an over-deepening of the main valley4 ,these streams1 however1 and others so far as could be determined1 were found to have normal profiles2 that is1 their grades become increasingly flatter toward their mouths4 ,the streams are cutting through the till cover and are not building alluvial cones where they join the lowland4 ,all their features1 in fact1 are characteristic of normal stream development4 ,throughout the length of the valley1 rock outcrops are found near the surface1 showing that the changes produced by the glacier were due to scouring rather than to the accumulation of glacial material4 ,except where stratified drift is collected locally in considerable quantity1 the glacial mantle is thin4 ,on the other hand1 it has been shown that glacial gouging was not sufficient in amount to affect the course of the stream4 ,the glacier simply cleaned off the soil and rotten rock from the surface1 slackening the stream here and hastening it there1 and by blocking the course with drift it forced the river at several places to depart slightly from its preglacial course4 ,the evidence shows1 therefore1 that if ,still ,river has suffered reversal1 glaciation is not responsible for the change1 and thus the first two hypotheses for explaining the history of the valley are eliminated4 ,there remain for discussion the third and fourth hypotheses2 the former being that reversal was effected in a very early stage in the development of the drainage1 the latter that no reversal has occurred4 ,the choice between these two hypotheses rests on evidence obtained in the ,umpog1 ,croton1 and other valleys of the ,danbury region4 ,this evidence is presented in the three following sections1 after which the former courses of ,still ,river will be discussed4 ,,the ,,still-,,saugatuck ,,divide ,,features ,,of ,,the ,,umpog ,,valley ,the valley of the ,umpog1 which extends from ,still ,river to the source of the ,saugatuck near ,west ,redding 7fig4 #g71 is a critical area in the study of the ,still ,river system4 ,it is possible that this valley once afforded an outlet for ,still ,river1 and it has been suggested that the ,housatonic formerly followed this route to ,long ,island ,sound4 ,the relation of this valley to the former drainage system of the ,danbury region demands1 therefore1 a careful examination of the features of the valleys occupied by ,umpog ,creek and the upper waters of the ,saugatuck1 and of the divide between those streams4 ,illustration3 ,fig4 #g4 ,map of ,umpog ,swamp and vicinity4 ,north of ,bethel the ,umpog occupies an open valley developed in limestone4 ,knolls of limestone rise to heights of about #dj feet above the floor of the valley and their upper surfaces are cut across the highly1 tilted beds4 ,this truncation1 together with a general correspondence in height1 suggests that these knolls1 as well as the rock terraces found between ,bethel and ,west ,redding1 and the limestone ridge which forms the divide itself1 are portions of what was once a more continuous terrace produced by stream erosion and that they determine a former river level4 ,the absence of accurate elevations and the probability of glacial scour make conclusions regarding the direction of slope of this dissected rock terrace somewhat uncertain4 ,as will be indicated later1 however1 it seems likely that these terrace remnants mark the course of a southward flowing river that existed in a very early stage in the development of the drainage4 ,south of ,bethel the old ,umpog valley1 has lost from one-third to one-half its width through deposits of stratified drift 7,pl4 ,,ii1 ,a and ,b74 ,on the west1 gravel beds lie against rock and till2 on the east1 deposits of sand and coarse gravel form a bench or terrace from #ejj to #gjj feet broad1 which after following the side of the valley for one-half mile1 crosses it diagonally and joins the western slope as a row of rounded hills4 ,through this drift the present stream has cut a narrow channel4 ,the narrowest part of the ,umpog valley is about one mile south of ,bethel4 ,farther upstream the valley expands into the flat occupied by ,umpog ,swamp1 which presents several interesting features4 ,the eastern1 southern1 and western sides of the swamp are formed of irregular masses of limestone and granite-gneiss #bj to #fj feet high4 ,near the northwestern edge of the swamp is a terrace-like surface cut on limestone4 ,its elevation is about the same as that of the beveled rock remnants lying in ,umpog valley north of ,bethel4 ,illustration3 ,state ,geol4 ,nat4 ,hist4 ,survey4 ,bull4 #cj4 ,plate ,,ii4 ,a4 ,view up the valley of ,umpog ,creek4 ,the valley dwindles in the distance to the railroad divide4 ,in the middle distance is ,umpog ,swamp2 in the foreground the edge of the southern end of row of ,kames which points down the valley4 ,b4 ,view down the valley of ,umpog ,creek4 ,to the left is the edge of limestone terrace2 in the middle distance is the ,catholic cemetery situated on a terrace of stratified drift2 on the right are mounds of stratified drift2 in the distance is the granite ridge bounding the valley on the east4 ,illustration3 ,fig4 #h4 ,profiles of rivers4 ,a4 ,profile of present ,still ,river and buried channel of ,umpog-,still ,river4 ,b4 ,profile of preglacial ,croton-,still ,river4 ,c4 ,profile of preglacial ,umpog-,still ,river4 ,solid lines show the present levels4 ,dotted lines show preglacial levels4 ,umpog ,swamp was formerly a lake but is now nearly filled with organic matter so that only a small remnant of the old water body remains4 ,soundings have revealed no bottom at #dc feet#aj and the depth to rock bottom is not less than #de feet4 ,the swamp situated one-half mile southwest of ,bethel has a depth to rock of #ce feet4 ,in their relation to the ,still ,river system these two swamps may be regarded simply as extensions of the ,umpog ,creek channel1 but when the elevations of their bottoms are compared with that of points to the north and south1 where the river flows on rock1 it will be seen that a profile results which is entirely out of harmony with the present profile of the river4 ,thus ,umpog ,creek falls #dj feet at the point where it spills over the rock ledge into the swamp1 and if the #de feet which measures the depth of ,umpog ,swamp be added1 the difference in level is seen to be at least #he feet4 ,a similar calculation locates the bottom of the smaller swamp near ,bethel at an elevation of #cdj feet above sea-level or on the same level as the bottom of ,umpog ,swamp4 ,in a straight line #b-a_/d miles north of ,bethel1 ,still ,river crosses rock at a level of #cej feet1 or #aj feet higher than the bottom of ,umpog ,swamp4 ,at ,brookfield1 #f-a_/b miles north of the mouth of the ,umpog1 the ,still crosses rock at #bfj feet1 and #d-a_/b miles farther north1 it joins the ,housatonic on a rock floor #bjj feet above sea-level 7fig4 #h1 ,a74 ,such a profile can be explained in either of two ways3 glaciers gouged out rock basins in the weak limestone1 or the river in its lower part has been forced out of its graded bed onto rock at a higher level4 ,probably both causes have operated1 but the latter has produced more marked effects4 ,umpog ,creek has its source in a small forked stream which rises in the granite hills east of the south end of ,umpog ,swamp4 ,after passing westward through a flat swampy area1 where it is joined by the waters from ,todd ,pond1 the stream turns north and follows a shallow rock gorge until ,umpog ,swamp is reached4 ,the divide which separates the present headwaters of the ,umpog from those of the ,saugatuck is a till-covered swampy flat about one-quarter mile east of ,todd ,pond4 ,this arrangement of tributary streams is correctly shown in fig4 #g and differs essentially from that shown on the ,danbury atlas sheet4 ,this divide owes its position to the effects of glaciation4 ,deposits of till and the scouring of the bed rock so modified the preglacial surface that the upper part of the ,saugatuck was cut off and made tributary to the ,umpog4 ,footnote #aj3 ,report by ,t4 ,t4 ,giffen1 #aijg4 ,,the ,,preglacial ,,divide ,in order to determine whether ,still ,river flowed southward through the ,saugatuck ,valley just before the advent of the ice sheet1 the borders of ,umpog ,swamp and the region to the south and east were examined4 ,it was found that ,umpog ,swamp is walled in on the south by ledges of firm crystalline limestone and that the rock-floored ravine leading southward from the swamp1 and occupied by the railroad1 lies at too high an elevation to have been the channel of a through-flowing stream4 ,a south-flowing ,still ,river1 and much less an ancient ,housatonic1 could not have had its course through this ravine just previous to glaciation4 ,a course for these rivers through the short valley which extends southeastward from ,umpog ,swamp is also ruled out1 because the bedrock floor of this hypothetical passageway is #bj feet higher than the floor of the ravine through which the railroad passes4 ,the eastern border of ,umpog ,swamp is determined by a ridge of limestone which separates the swamp from lowlying land beyond4 ,this ridge is continuous1 except for the postglacial gorge cut by the tributary entering from the east1 and must have been in existence in preglacial times4 ,the entire lowland east of this limestone ridge possesses a unity that is not in harmony with the present division of the drainage4 ,the streams from this hillside and those from the west may have joined in the flat-floored valley at the head of the ,saugatuck and from there flowed into the ,saugatuck system4 ,the former divide then lay in a line connecting the limestone rim of the swamp with the tongue of highland which the highway crosses south of ,todd ,pond 7fig4 #g74 ,,the ,,still-,,croton ,,divide ,,introduction ,the deep valley extending from the ,danbury ,fair ,grounds to the ,east ,branch ,reservoir in the ,croton ,river system1 has given rise to the suggestion that the course of the ,housatonic formerly may have been along the line of ,still and ,croton rivers and thence to the ,hudson4#aa ,from the evidence of the topographic map alone1 this hypothesis appears improbable4 ,the trend of the larger streams in western ,connecticut is to the south and southeast2 a southwesterly course1 therefore1 would be out of harmony with the prevailing direction of drainage4 ,also1 the distance from the present mouth of ,still ,river to tidewater by the ,still-,croton route is longer than the present route by way of the ,housatonic4 ,footnote #aa3 ,hobbs1 ,w4 ,h41 ,still rivers of western ,connecticut3 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ac1 p4 #be1 #aija4 ,,features ,,of ,,still ,,river ,,valley ,,west ,,of ,,danbury ,from ,danbury to its source ,still ,river occupies a valley whose features are significant in the history of the drainage4 ,between ,danbury and the ,fair ,grounds 7fig4 #a7 the valley is a ,v-shaped ravine #a-a_/b miles long1 well proportioned to the small stream now occupying it but entirely too narrow for the channel of a large river4 ,along the valley are outcrops of schist1 and granite rock is present on both sides of the valley for a distance of about one-quarter mile4 ,part of the valley is a mere cleft cut in the rock and is unglaciated4 ,at the ,danbury ,fair ,grounds the valley opens out into a marshy plain1 through which the river meanders and receives two tributaries from the south4 ,the plain1 which extends beyond ,lake ,kanosha on the west1 has a generally level surface but is diversified in places by mounds of stratified drift4 ,near the railroad a rock outcrop was found which gives a clue to the nature of the broad lowland4 ,the rock consists mainly of schist1 but on the side next the valley there is a facing of rotten limestone4 ,this plain1 like all the others in this region1 is a local peneplain developed on soluble limestone4 ,a better example could not be found to prove the fallacy of the saying that a broad valley proves the existence of a large river4 ,the plain is simply a local expansion of a valley which on each side is much narrower4 ,no other river than the one flowing through it can have been responsible for the erosion1 for the plain is enclosed by hills of gneiss and schist 7,pl4 ,,iii74 ,at ,mill ,plain the valley is crowded by ragged rock outcrops which jut into the lowland4 ,here the river occupies a ravine cut in till near the north side of the valley4 ,west of ,mill ,plain station the valley is encumbered with ridges of stratified drift1 interspersed with heavy accumulations of till4 ,near ,andrew ,pond the true width of the valley--one-eighth mile--is shown by rock outcrops on both the north and south slopes4 ,the valley at this point gives no indication of narrowing toward the headwaters2 in fact1 it becomes broader toward the west4 ,between ,andrew ,pond and ,haines' ,pond is the divide which separates the waters of the ,still system from those of the ,croton4 ,it consists of a jumbled mass of morainal hills1 seemingly of boulder clay1 that rise from #ej to #fj feet above the level of the ponds4 ,the divide is thus merely a local obstruction in what was formerly a through drainage channel4 ,,the ,,still-,,croton ,,valley ,it is evident that before the advent of the glacier a stream must have flowed through the ,still-,croton valley past the present divide in order to have excavated the rock valley there found4 ,the ,housatonic could not have flowed west through this valley if it was as narrow and shallow as is indicated by known rock outcrops2 the river could have flowed through it only in a deep narrow gorge which was later buried under drift1 but the evidence at hand does not support this view4 ,illustration3 ,state ,geol4 ,nat4 ,hist4 ,survey ,bull4 #cj4 ,plate ,,iii4 ,limestone ,plain southwest of ,danbury1 in which are situated the ,danbury ,fair ,grounds and ,lake ,kanosha4 ,it is most probable that this valley was made by the preglacial ,croton ,river4 ,this explanation demands no change in the direction of ,still and ,croton ,rivers but calls for a divide at some point east of the present one4 ,from a divide between the ,fair ,grounds and ,danbury1 a small stream may be supposed to have flowed toward the east1 joining the larger northern branch of the ,still at a point near the middle of the city of ,danbury4 ,the stream flowing westward from this divide formed the headwaters of one branch of the ,croton system4 ,the presence of till in a ravine can be used as a criterion for locating the site of a former divide1 for where till is present in the bed of a stream the channel is of preglacial date4 ,where the river crosses a divide it should be cutting through rock1 though till may be present on the valley slopes4 ,judged by this test1 the old divide was situated either just east of the ,fair ,grounds plain or at the east end of the ravine described in the preceding topic4 ,of these two positions the one near the ,fair ,grounds seems the more likely 7fig4 #a71 for at this place the river has excavated a recent channel with steep sides in gneissoid rock4 ,the absence of the limestone at this point may be sufficient in itself to explain the location of the divide4 ,exact measurements of the drift in the upper ,still valley are needed in order to establish this hypothesis completely and to plot the old channel1 but the position of the rock floor of the former channel extending westward from the ,fair ,grounds may be fixed approximately4 ,the rock at the assumed divide now stands at #dbj feet above sea-level and it is reasonable to assume that ten feet has been removed by glacial scouring and postglacial erosion1 making the original elevation #dcj feet4 ,the present divide between ,andrew ,pond and ,haines' ,pond has an elevation of #dfj1 but the bedrock at this place is buried under #fj feet of drift1 so that the valley floor lies at #djj feet4 ,according to these estimates the stream which headed east of the ,fair ,grounds had a fall of #cj feet before reaching the site of the present ,haines' ,pond 7fig4 #h1 ,b74 ,,glacial ,,lake ,,kanosha ,when the ,croton ,branch was beheaded by drift choking up its valley west of ,andrew ,pond1 the ponded waters rose to a height of from #bj to #cj feet and then overflowed the basin on the side toward ,danbury4 ,the outlet was established across the old divide1 and as the gorge by which the water escaped was cut down1 the level of the ponded waters was lowered4 ,at the same time1 also1 the lake was filled by debris washed into it from the surrounding slopes4 ,thus the present flat plain was formed and the old valley floor1 a local peneplain developed on the limestone1 was hidden4 ,,divides ,,in ,,the ,,highlands ,,south ,,of ,,danbury ,the mountain mass to the south and southwest of ,danbury1 including ,town ,hill and ,spruce1 ,moses1 and ,thomas mountains1 is traversed by a series of parallel gorges trending nearly north and south 7fig4 #b74 ,about midway in each valley is a col1 separating north and south-flowing streams4 ,two of the valleys1 those between ,spruce and ,moses mountains1 and ,thomas ,mountain and ,town ,hill1 form fairly low and broad passes4 ,they were examined to see whether either could have afforded a southerly outlet for ,still ,river4 ,the rock composing the mountains is granite-gneiss and schist with an average strike of ,n #cj deg4 ,w1 or very nearly in line with the trend of the valleys4 ,the gneiss was found to be characteristic of the high ridges and schist to be more common in the valleys4 ,no outcrops of limestone were found on the ridges1 but at two or three localities limestone in place was found on low ground4 ,from the facts observed it is evident that the stronger features of the relief are due to the presence of bodies of resistant rock1 whereas the valleys are due to the presence of softer rock4 ,the series of deep parallel valleys is attributed to the presence of limestone rather than schist4 ,the gorge between ,spruce and ,moses mountains1 locally called ,sugar ,hollow1 narrows southward as it rises to the col1 and the rock floor is buried under till and stratified drift to depths of #be to #ej feet4 ,nevertheless it is probable that the valley was no deeper in preglacial time than it is now4 ,the plan of the valley with its broad mouth to the north favored glacial scour so that the ice widened and deepened the valley and gave it a ,u form4 ,scouring and filling are believed to have been about equal in amount1 and the present height of the divide1 about #dgj feet1 may be taken as the preglacial elevation4 ,this is #gj feet higher than the rock floor of the divide at ,west ,redding4 ,the pass could not1 therefore1 have served as an outlet for ,still ,river4 ,the valley west of ,town ,hill is similar in form and origin to ,sugar ,hollow4 ,the water parting occurs in a swamp1 from each end of which a small brook flows4 ,the height of the pass in this valley--#eij feet-- precludes its use as an ancient outlet for ,still ,river4 ,likewise the valley east of ,town ,hill affords no evidence of occupation by a southward through-flowing stream4 ,,the ,,ancient ,,still ,,river ,the conclusion that the ,still-,umpog was not reversed by a glacial dam does not preclude the possibility that this valley has been occupied by a south-flowing stream4 ,it is probable that in an early stage in the development of the drainage1 the streams of the ,danbury region reached ,long ,island ,sound by way of the ,still-,umpog-,saugatuck valley4 ,along this route1 as described under the heading ,the ,still-,saugatuck ,divide1 is a fairly broad continuous valley at a higher level than the beds of the present rivers4 ,a south-flowing river1 as shown in fig4 #i1 brings all the drainage between ,danbury and the ,housatonic into normal relations4 ,this early relationship of the streams was disturbed by the reversal of the waters of the ancient ,still in the natural development of a subsequent drainage4 ,the ,housatonic lowered the northern end of the limestone belt1 in the region between ,new ,milford and ,stillriver village1 faster than the smaller south-flowing stream was able to erode its bed4 ,eventually a small tributary of the ,housatonic captured the headwaters of the south-flowing river1 and by the time the latter had been reversed as far south as the present divide at ,umpog ,swamp1 it is probable that the advantage gained by the more rapid erosion of the ,housatonic was offset by the ,saugatuck's shorter course to the sea4 ,as a result the divide between ,still and ,saugatuck ,rivers at ,umpog ,swamp had become practically stationary before the advent of the glacier4 ,the complex history of ,still ,river is not fully shown in the stream profile1 for the latter is nearly normal1 except in the rock basins in the valley of the ,umpog4 ,this is due to the fact that changes in the course of the ,still1 caused by the development of a subsequent drainage through differential erosion1 were made so long ago that evidence of them has been largely destroyed4 ,the foregoing conclusion practically eliminates hypothesis ,,iv--that the ,still developed from the beginning as a subsequent stream in the direction in which it now flows4 ,this hypothesis holds good only for the short portion of the lower course of the present river1 that is1 the part representing the short tributary of the ,housatonic which captured and reversed the original ,still4 ,,departures ,,of ,,still ,,river ,,from ,,its ,,preglacial ,,channel ,between ,danbury and ,beaver ,brook ,mountain the ,still departs widely from its former channel1 as shown in fig4 #f4 ,at the foot of ,liberty ,street in ,danbury the river makes a sharp turn to the southeast1 flows through a flat plain1 and for some distance follows the limestone valley of the ,umpog1 meeting the latter stream in a swampy meadow4 ,it then cuts across the western end of ,shelter ,rock in a gorge-like valley not over #bjj feet wide4 ,outcrops of a gneissoid schist on the valley sides and rapids in the stream bear witness to the youthfulness of this portion of the river channel4 ,an open valley which extends from the foot of ,liberty ,street in a northeasterly direction 7the railroad follows it7 marks the former course of ,still ,river1 but after the stream was forced out of this course and superimposed across the end of ,shelter ,rock by the accumulation of drift in the central and northern parts of the valley1 it was unable to regain its old channel until near ,beaver ,brook ,mountain4 ,the deposits of drift not only have kept the ,still confined to the eastern side of its valley but have forced a tributary from the west to flow along the edge of the valley for a mile before it joins its master stream4 ,about a mile north of ,brookfield ,junction1 ,still ,river valley begins to narrow1 and at ,brookfield the river1 here crowded to the extreme eastern side1 is cutting a gorge through limestone4 ,the preglacial course of the ,still in the ,brookfield region seems to have been near the center of the valley where it was joined by ,long ,brook and other short1 direct streams draining the hillsides4 ,the glacier1 however1 left a thick blanket of drift in the middle of the valley which turned the ,still to the east over rock and forced ,long ,brook to flow for more than a mile along the extreme western side of the valley4 ,illustration3 ,fig4 #i4 ,early stage of the ,rocky-,still ,river1 antedating preglacial course shown in figure #d4 ,the broad valley through which the ,still flows in the lower part of its course extends northward beyond it for over two miles1 bordering the ,housatonic ,river4 ,at ,lanesville near the mouth of the ,still1 the river has cut a gorge #cj feet deep and one-quarter mile long in the limestone4 ,upstream from this gorge the river meanders widely in a flat valley1 whereas on the downstream side it has cut a deep channel in the drift in order to reach the level of the ,housatonic4 ,there is room in the drift-covered plain to the west for a buried channel of ,still ,river which could join the ,housatonic at any point between ,new ,milford and ,stillriver station4 ,if the depth of the drift be taken at #be feet1 there would seem to be no objection to the supposition that the ,still initially joined its master stream opposite ,new ,milford1 as shown in fig #f4 ,after the limestone had been worn down to approximate baselevel1 the tendency of the ,still would have been to seek an outlet farther south in order to shorten its course and reach a lower level on the ,housatonic4 ,this stage in the evolution of the river may not have been reached before the ice age1 and it is thus possible that glacial deposits may have pushed the river to the extreme southern side of its valley1 superimposed it over rock1 and forced it to cut its way down to grade4 ,,suggested ,,courses ,,of ,,housatonic ,,river ,as possible former outlets for the ,housatonic1 ,hobbs has suggested the ,still-,umpog-,saugatuck valley or the ,still-,croton valley 7by way of the ,east ,branch ,reservoir7#ab1 whereas ,crosby has suggested the ,ten ,mile-,swamp ,river-,muddy ,brook-,croton ,river valley 7by way of ,webatuck1 ,wing's ,station1 and ,pawling71 or the ,fall's ,village-,limerock-,sharon- ,webatuck ,creek-,ten ,mile valley4#ac ,the sketch map1 fig4 #aj1 indicates the courses just outlined and one other by way of the ,norwalk4 ,the latter is the route followed by the ,danbury and ,norwalk ,division of the ,housatonic ,railroad4 ,it is natural to assume that the ,housatonic might have occupied anyone of these lines of valleys1 particularly where they are developed on limestone and seem too broad for the streams now occupying them4 ,nevertheless1 although each of these routes is on soft rock and some give shorter distances to the sea than the present course1 it is highly improbable that the ,housatonic ever occupied any of these valleys4 ,for had the river once become located in a path of least resistance1 such as is furnished by any of these suggested routes1 it could not have been dislodged and forced to cut its way for #be miles through a massive granitic formation1 as it does between ,still ,river and ,derby1 without great difficulty 7,pl4 ,,iv1 ,a74 ,illustration3 ,fig4 #aj4 ,five suggested outlets of ,housatonic ,river4 ,an inspection of the larger river systems of ,connecticut shows that the streams composing them exhibit two main trends4 ,likewise1 the courses1 of the larger rivers themselves1 whether trunk streams or tributaries1 combine these two trends1 one of which is northwest-southeast and the other nearly north-south4 ,the north-south drainage lines are the result of geologic structure1 and many broad1 flat-floored valleys1 often apparently out of proportion to the streams occupying them1 have this direction4 ,on the other hand1 the northwest-southeast drainage lines across the strike of formations1 coincide with the slope toward the sea of the uplifted peneplain whose dissected surface is represented by the crests of the uplands4 ,the valleys of streams with this trend are generally narrow1 and some are gorges where resistant rock masses are crossed4 ,the northwest-southeast trends of master streams thus were determined initially by the slope of the peneplain1 whereas the north-south trends represent later adjustments to structure4 ,it is concluded1 therefore1 that the ,housatonic between ,bulls' ,bridge and ,derby 7fig4 #aj71 had its course determined by the slope of the uplifted peneplain and is antecedent in origin4 ,the old headwaters extended northwest from the turn in the river near ,bull's ,bridge1 whereas that part of the river above ,bull's ,bridge was initially a minor tributary4 ,this tributary1 because of its favorable situation1 in time captured all the drainage of the extensive limestone belt to the north and then became part of the main stream4 ,the lower ,housatonic1 therefore1 has always maintained its ancient course diagonal to the strike of formations1 and differential erosion1 which reaches its maximum expression in limestone areas1 is responsible for the impression that the ,still ,river lowland and other valleys west of the ,housatonic may once have been occupied by the latter stream4 ,illustration3 ,state ,geol4 ,nat4 ,hist4 ,survey ,bull4 #cj4 ,plate ,,iv4 ,a4 ,view down the ,housatonic ,valley from a point one-half mile below ,still ,river station4 ,pumpkin ,hill1 a ridge of resistant schist and quartzite1 stands on right4 ,a small island lies in the river4 ,b4 ,part of the morainal ridge north of ,danbury4 ,till capped by stratified drift one mile north of ,shelter ,rock4 ,footnote #ab3 ,hobbs1 ,w4 ,h41 ,still rivers of western ,connecticut3 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ac1 p4 #be1 #aija4 ,footnote #ac3 ,crosby1 ,w4 ,o41 ,notes on the geology of the sites of the proposed dams in the valleys of the ,housatonic and ,ten ,mile rivers3 ,tech4 ,quart41 vol4 #ac1 p4 #abj1 #aijj4 ,,glacial ,,deposits ,,beaver ,,brook ,,swamp ,a broad belt of limestone extends along the eastern side of the granite ridge of ,shelter ,rock and in preglacial time formed a broad-bottomed valley whose master stream had reached old age4 ,when the glacier came it hampered the drainage by scooping out the rock bottom of the valley in places and by dropping deposits at the mouth of ,beaver ,brook valley1 thus forming ,beaver ,brook ,swamp or ,the ,flat1 as it is called 7fig4 #f74 ,among the deposits at the southern end of ,beaver ,brook ,swamp is considerable stratified drift in the form of smoothly rounded hills or kames1 which are situated both on the border of the valley and in the swamp4 ,till containing medium-sized boulders of granodiorite-gneiss occurs along the road which borders the east side of the densely wooded swamp4 ,along the northeastern border of the swamp is a flat-topped terrace of till1 perhaps a lateral moraine1 through which a small stream heading to the north has cut a ,v-shaped ravine4 ,a lobe of fine till extends into the valley from the northeast and narrows the outlet4 ,between the railroad and highway1 which cross the northern end of the swamp1 is an irregular wooded eminence of rock1 partly concealed by a veneer of drift4 ,between this knoll and ,shelter ,rock are heavy deposits of sand in the form of a short1 broad terrace with lobes which point into the ,still ,river valley4 ,a similar terrace is found to the northwest on the opposite side of the valley4 ,at the northern end of ,shelter ,rock along the blind road leading to the summit is a peninsula-like body of drift which contains huge granite boulders mixed here and there with pockets of sand and gravel4 ,stratified drift was found at the foot of the hill1 and till overlying it higher up4 ,the more usual arrangement is boulder clay overlain by modified drift1 the first being laid down by the ice itself1 the second being deposited by streams from the melting glacier in its retreat4 ,huge boulders1 many ten feet or more in diameter1 are strewn over the northern slope of ,shelter ,rock4 ,,deposits ,,northeast ,,of ,,danbury ,north of the railroad1 opposite ,shelter ,rock 7fig4 #f71 is a most interesting flat-topped ridge of drift which topographically is an extension of the higher rock mass to the northwest4 ,in this drift mass are to be found in miniature a number of the forms characteristic of glacial topography4 ,the broad-topped gravel ridge slopes sharply on the north into a flat-bottomed ravine which is evidently part of the ,still ,river lowland4 ,this portion of the valley has been shut off by drift deposits4 ,the drainage has been so obstructed that the stream in the ravine turns northeast away from its natural outlet4 ,in the valley of ,x brook 7fig4 #a7 are terraces1 esker-like lobes1 and detached mounds of stratified drift resting on a foundation of till4 ,along the eastern border of the hill is to be seen the contact between two forms of glacial deposits 7,pl4 ,,iv1 ,b74 ,a mass of stratified drift overlies a hummocky deposit of coarse till1 but large boulders occurring here and there on top of the stratified drift show that the ice-laid and water-laid materials were not completely sorted4 ,boulders seem to have been dropping out of the ice at the same time that gravel was being deposited4 ,boulders of granite-gneiss eight feet or more in diameter1 carried by the ice from the hills to the north and northeast1 are strewn at the foot of the hill4 ,,deposits ,,between ,,beaver ,,brook ,,mountain ,,and ,,mouth ,,of ,,still ,,river ,about a mile beyond ,beaver ,brook ,mountain1 the railroad cuts through the edge of a hill #hj feet in height exposing a section consisting of distinctly stratified layers of fine white quartz sand1 coarser yellowish sand1 and small round pebbles4 ,the quartz sand was used at one time in making glass4 ,farther east where the two tracks of the ,new ,york and ,new ,england railroads converge1 a cut shows a section of at least #dj feet of boulder clay4 ,near the river1 limestone boulders are common1 indicating that the valley to the north was degraded to some extent by the glacier4 ,illustration3 ,state ,geol4 ,nat4 ,hist4 ,survey ,bull4 #cj4 ,plate ,v4 ,a4 ,kames in ,still ,river ,valley west of ,brookfield ,junction4 ,b4 ,till ridges on the western border of ,still ,river ,valley1 south of ,brookfield4 ,in the valley at ,brookfield ,junction and on its western side1 are thick deposits of clean sand4 ,one mile north of ,brookfield ,junction1 along the western border of the valley1 an esker follows an irregular course for several hundred yards approximately parallel to the river and terminates at its southern end in a group of kames 7,pl4 ,v1 ,a and ,b74 ,opposite the point where these accumulations occur1 is a terrace-like deposit of till4 ,between the gorge at ,brookfield and the mouth of ,still ,river1 swampy areas1 flat meadows1 and small hills of drift occur4 ,in comparison with the ,still ,river lowland1 the flat land east of ,green ,mountain may be called a plateau4 ,the step between the two is made by an east-facing rocky slope1 the outline of which has been softened by a lateral moraine separated from the plateau edge by a small ravine4 ,on the lowland below the moraine is a group of kames4 ,near ,lanesville 7fig4 #f71 are thick deposits of water-laid material1 including a hill of gravel near the river having a large bowl-shaped depression on one side formed by the melting of an ice block4 ,two and a half miles south of ,lanesville on the west side of the lowland1 a wooded esker extends for about one-quarter mile parallel to the valley axis and then merges into the rocky hillside4 ,,lakes ,the lakes of this region are of two kinds3 7#a7 those due to the damming of river valleys by glacial deposits and 7#b7 rock basins gouged out by the ice4 ,among the lakes which owe their origin to drift accumulations in the valleys are ,andrew and ,haines' ponds at the head of ,still ,river4 ,these are properly parts of the ,croton ,river system1 but ,andrew ,pond has been held back by the deep filling of boulder clay in the valley4 ,lake ,kanosha1 in the same valley1 is a shallow lake formed in the drift4 ,the lake south of ,spruce ,mountain at the head of the ,saugatuck seems to be enclosed by drift alone4 ,neversink ,pond1 ,barses ,pond1 ,creek ,pond1 and ,leonard ,pond are the remnants of larger water bodies now converted into swamps4 ,squantz ,pond and ,hatch ,pond have dams of drift4 ,eureka ,lake and ,east ,lake appear to be rock basins whose levels have been raised somewhat by dams of till4 ,great ,mountain ,pond and ,green's ,pond1 between ,great ,mountain and ,green ,mountain1 are surrounded by rock and their level has been raised several feet by artificial dams4 ,great ,mountain ,pond is at least #ej feet above the level of ,green ,pond and separated from it by a rock ridge 7fig4 #b74 ,,history ,,of ,,the ,,glacial ,,deposits ,a tongue of the glacier is supposed to have lain in the valley of the ,umpog and gradually retreated northward after the ice had disappeared from the uplands on either side4 ,the ridge of intermediate height built of limestone and schist1 which extends down the middle of the valley1 was probably covered by ice for some time after the glacier had left the highlands4 ,when the mountain mass extending from ,pine ,mountain to ,town ,hill west of the ,umpog ,basin and the granite hills to the east terminating in ,shelter ,rock are considered in their relation to the movement of the ice1 it is apparent that the valley of the ,umpog must have been the most direct and lowest outlet for glacial streams south of ,danbury4 ,these streams built up the terraces and other deposits of stratified drift which occupy the valley between ,bethel and ,west ,redding4 ,the heavy deposits of till near ,west ,redding mark a halt in the retreating glacier4 ,the boulders at this point are large and numerous1 and kames and gravel ridges were formed4 ,the deposits at the divide1 supposed to have formed a glacial dam which reversed the ,umpog1#ad are much less heavy than at points short distances north and south of the water parting4 ,as the ice retreated1 sand and gravel in the form of terraces accumulated along the margin of the ,umpog valley1 where the drainage was concentrated in the spaces left by the melting of the ice lobe from the hillside4 ,among these deposits are the bodies of sand and gravel which lie against the rocky hillslopes most of the way from the ,umpog-,saugatuck divide to ,bethel4 ,north of ,bethel1 the drainage seems to have been gathered chiefly in streams flowing on each side of the low ridge occupying the center of the valley2 consequently the gravel was deposited along the sides and southern end of the ridge and in the sag which cuts across its northern end4 ,the row of kames at the north end of ,umpog ,swamp1 several knolls of drift in ,bethel1 and the kame-like deposits and esker north of ,grassy ,plain were laid down successively as the ice retreated down the valley4 ,during this period1 the drainage was ponded between the ice front and the ,umpog-,saugatuck divide4 ,uncovering the ,still-,croton valley did not give the glacial drainage any lower outlet than the ,umpog-,saugatuck divide afforded 7fig4 #h1 ,b and ,c47 ,the heavy deposits of boulder clay forming the moraine which blocks the ,rocky ,river valley indicate the next halting place of the glacier4 ,in this period the ice margin formed an irregular northeast-southwest line about a mile north of ,danbury4 ,the country west and south of ,danbury was thus uncovered1 but the lower part of ,still ,river valley was either covered by the ice sheet or occupied by an ice lobe4 ,the drainage was1 therefore1 up the river valley1 and being concentrated along the valley sides resulted in the accumulation of sand and gravel at the foot of rocky slopes4 ,it is possible that an ice lobe extended down the old ,rocky ,river valley1 perhaps occupying much of the country between ,beaver ,brook ,mountain and the high ridge west of the valley4 ,the streams issuing from this part of the ice front would have laid down the eskers and kame gravels north of ,danbury and the thick mantle of drift over which ,still ,river flows through the city4 ,as would be expected1 this accumulation of material ponded all the north-flowing streams--,umpog ,creek1 ,beaver ,brook1 and smaller nameless ones--and at the same time pushed ,still ,river1 at its mouth1 to the southern side of its valley4 ,beaver ,brook valley1 ,umpog valley1 and all the ,danbury basin must have been flooded during this period up to the height of the railroad divide4 ,within the area covered by the city1 the valley was filled up to at least #gj feet and probably much more than that above its former level4 ,flowing at this higher level1 the river was thrown out of its course and here and there superimposed on hard rock--as1 for example1 at ,shelter ,rock4 ,that part of the drainage coming down the valley opposite ,beaver ,brook met the drainage from ,still ,river ice lobe in the valley north of ,shelter ,rock1 and as a result heavy deposits of stratified drift were laid down4 ,the peninsula-like mass of drift beyond the river north of ,shelter ,rock appears from its form to have been built up as the delta of southward and eastward-flowing streams2 probably the drainage from the hilltops united with streams coming down the two valleys4 ,the lobes of stratified drift extending from the ridge may have been built first1 and later the connecting ridge of gravel which forms the top of the hill may have accumulated as additional material was washed in1 tying together the ridges of gravel along their western ends4 ,the mingling in this region of stratified drift of all grades of coarseness indicates the union in the same basin of debris gathered from several sources4 ,between ,danbury and ,new ,milford no moraine crosses either the ,rocky or the ,still valley1 but the abundance of till which overspreads the whole country indicates a slowly retreating glacier well loaded with rock debris4 ,the mounds of stratified drift scattered along the valley doubtless represent the deltas of streams issuing from the ice front4 ,the waters of ,rocky ,river were ponded until the outlet near ,jerusalem was uncovered and the disappearance of ice from the ravine below allowed an escape to the ,housatonic4 ,stratified drift is present in greatest amount along the valleys of ,still ,river and the west fork of ,rocky ,river1 indicating that these were the two chief lines of drainage4 ,the uplands are practically without stratified drift4 ,along the valley of the ,housatonic1 glacial material is chiefly in the form of gravel terraces2 they extend from ,gaylordsville to ,new ,milford1 in some places on one side only1 in others on both sides of the river4 ,part of these gravel benches are kame terraces1 as shown by their rolling tops and the ravine which separates the terrace from the hillside2 others may have been made by the river cutting through the mantle of drift which was laid down in the period of land depression at the time of glacial retreat1#ae or they may be a combination of the two forms4 ,in many places by swinging in its flood plain1 the river has cut into the terraces and left steep bluffs of gravel4 ,the valley of ,womenshenuck ,brook above ,merwinsville contains heavy deposits of stratified drift1 indicating that this broad valley which extends from ,kent on the ,housatonic to ,merwinsville was an important channel for the water which flowed from the melting ice4 ,footnote #ad3 ,rice1 ,w4 ,n4 and ,gregory1 ,h4 ,e41 ,manual of the ,geology of ,connecticut3 ,conn4 ,geol4 and ,nat4 ,hist4 ,survey ,bull4 #f1 pp4 #cd-ce1 #aijf4 ,footnote #ae3 ,hobbs1 ,w4 ,h41 op4 cit4 99 99 99 99 99 ,transcriber's ,notes3 ,with the following exceptions1 the text presented here is that obtained through scanned images from an original copy of the manuscript4 ,possible ,typographic ,errors ,corrected occuying occupying ,,plate ,,ii ,a4 of repeated ,emphasis ,notation3 text - italicized text - bold text - small caps