,illustration3 ,cover ,picture3 ,selected 8buttons0 from the clay bank along the beach at ,button ,bay ,state ,park4 7#j4h74 ,,the ,,geology ,,of ,,button ,,bay ,,state ,,park ,by ,,harry ,w4 ,,dodge1 ,,jr4 ,,department ,,of ,,forests ,,and ,,parks ,perry ,h4 ,merrill1 ,director ,,vermont ,,development ,,department ,,vermont ,,geological ,,survey ,charles ,g4 ,doll1 ,state ,geologist #aifb ,,the ,,geology ,,of ,,button ,,bay ,,state ,,park ,by ,harry ,w4 ,dodge1 ,jr4 ,,introduction ,button ,bay ,state ,park is located on the eastern shore of ,lake ,champlain with lake frontage on ,button ,bay 7see maps1 ,figs4 #a and #b74 ,this ,vermont ,state ,park is reached from the nearest large town1 ,vergennes1 by proceeding southwest1 toward ,addison1 on ,state ,route #bb;,a for 4#be miles beyond the bridge over ,otter ,creek1 thence1 right on the ,basin ,harbor-,panton road for another #a4d miles to the first road entering from the right4 ,turn right on this1 the ,basin ,harbor road1 and proceed for #d4e miles1 thence1 left for #a4d miles to ,button ,bay ,state ,park 7see map1 ,fig4 #b1 note arrows74 ,a more direct road is planned to connect the ,basin ,harbor ,road with the ,park1 however1 this route has still not been completed4 ,prior to its present name1 ,button ,bay1 the 8sickle-shaped bay0 on which ,button ,bay ,state ,park is located was termed ,button ,mould ,bay#a4 ,in 8,the ,journal of ,william ,gilliland0 which is found in the 8,pioneer ,history of the ,champlain ,valley0 by ,winslow ,c4 ,watson1 ,albany1 #ahfc1 and under the date of ,september #g1 #agfe1 is found an entry which speaks of 8his 7,gilliland7 overtaking #8the ,governors and other gentlemen'#b at ,button ,mould ,bay1 and going aboard their sloop40 ,a book of charts by ,captain ,william ,chambers contains one entitled 8,baye du ,roche ,fendue 7,split-,rock ,bay7 and the soundings taken in ,august #aggi40 ,at the upper corner of the chart is the name 8,button ,mould ,bay40 ,the first appearance of the shortened version1 ,button ,bay1 seems to be in ,whitelaw's map of #agif which was used as the frontispiece of the ,census volume1 8,heads of ,families1 ,vermont1 #ahjj40 ,illustration3 ,,figure #a ,,map ,,of ,,west-,,central ,,vermont ,,and ,,eastern ,,new ,,york ,illustration3 ,,figure #b ,why the name ,button ,bay8 ,h4 ,m4 ,seely 7#aiaj1 p4 #bgd7c when discussing the shoreline of this bay states1 8,besides shells1 concretions#d1 some of strange imitative forms 7many shaped like animals71 are loosened from the clay40 ,he goes on to say that a 8form particularly abundant in the banks of the bay 7and on the beach7 has the shape and size of a turned wood button-mold 7mold is commonly spelled #8mould' by the ,british71 a disc with a hole in the center1 plane 7flat7 on one side and convex on the other0 7see ,fig4 #c and cover picture74 ,the abundance of these button mold-shaped concretions obviously led to the older name1 ,button ,mould ,bay which was later shortened to ,button ,bay4 ,,the ,,geology ,,of ,,button ,,bay ,,state ,,park ,if the visitor confines his wanderings to the ,state ,park the most conspicuous geological features1 or clues to the ,park's past history1 are concentrated in the clay banks and adjacent beach which border ,lake ,champlain 7see ,fig4 #d74 ,the clays which cover the entire ,park record thousands of years of rather recent events1 geologically speaking#e1 which took place in the ,champlain ,valley4 ,these clays also record a very significant phase in the development of present ,lake ,champlain4 ,before discussing the clays it will be necessary to outline some of the geological events which preceded the deposition of the clays1 that is1 some of those events which took place as the last glacial ice lobe slowly retreated up the ,champlain ,valley and into ,canada4 ,the author has borrowed heavily from an article by ,donald ,h4 ,chapman entitled 8,late-,glacial and ,post-glacial ,history of the ,champlain ,valley0 which was published in the #aida-aidb 8,report of the ,state ,geologist on the ,mineral ,industries and ,geology of ,vermont1 twenty-third of 7the7 ,series40 ,illustration3 ,figure #c4 ,water-worn concretions seen on the beach of ,button ,bay ,state ,park4 ,the button-mold shape of some concretions led to the incorporation of the word 8,button0 in the name ,button ,bay 7,originally1 ,button-,mould ,bay74 ,the chisel portion of the ,alpine ice ax head is about #e inches long4 ,during the final retreat of the last ice sheet to invade the ,new ,england states 7some #aa1jjj to #ab1jjj years ago7 an ice lobe1 which occupied the ,hudson-,champlain ,valley1 slowly wasted northward toward the ,canadian border4 ,melt-water derived from the melting glacial ice together with atmospheric water 7rain and snow7 formed a succession of lakes dammed on the north by the glacial ice4 ,these lakes emptied to the south through the ,hudson ,valley4 ,this succession of lakes and intermediate lake stages will be discussed in the following paragraphs4 ,illustration3 ,figure #d4 ,view of beach1 ,button ,bay ,state ,park1 looking toward the southeast4 ,the beach demonstrates several water-level and storm-level debris lines4 ,note the conspicuous lack of sand on this 8clay0 beach4 ,the oldest lake recognized by the geologists is termed 8,lake ,albany0 and was confined to the ,hudson ,valley4 ,at this time the area of present-day ,lake ,champlain1 north of the ,hudson ,valley1 was still covered by glacial ice which was slowly melting as the general regional climate throughout ,new ,england became warmer and warmer4 ,soon the whole ,hudson ,valley region began to rise#f out from beneath the lake waters and 8,lake ,albany0 shallowed4 ,eventually a rock ledge emerged just south of ,schuylerville1 ,new ,york 7actually at ,coveville1 ,new ,york7 over which the waters from a new lake1 ,lake ,vermont1 began to flow4 ,lake ,vermont1 with its rock ledge dam at ,coveville1 began to expand northward as the ice front retreated up the ,champlain ,valley4 ,several distinct stages in its development are now recognized in features#g demonstrating past lake levels which are abundantly displayed close to ,button ,bay ,state ,park4 ,the 8lake-level indicators0 or features tell us1 in addition to the number of distinct lake stages in a given area1 something about past earth movements4 ,a 8line of lake-level-elevation0#h is drawn through those features outlining each past lake or lake stage followed by a comparison of each line with those lines constructed for older and younger lakes or lake stages4 ,if1 for any two lake-level lines compared1 these lines are not parallel1 it can be assumed that the earth's crust was tilted during the time between the formation of their lake-level features4 ,this idea of tilting of the earth's surface1 which is supported through the study of successive lake levels1 has proven the key to the present status of ,lake ,champlain4 ,at the beginning of its history ,lake ,vermont emptied to the south through an outlet channel located in the vicinity of ,coveville1 ,new ,york 7see map1 ,fig4 #e;,a74 ,this stage in the development of ,lake ,vermont1 often referred to as the ,coveville ,stage1 saw lake waters fill the ,champlain ,valley from the ,green ,mountains on the east to a position west of the present ,new ,york-,lake ,champlain shoreline4 ,such ,vermont towns as ,middlebury1 ,vergennes1 ,hinesburg1 ,burlington and ,colchester would have been submerged beneath the lake waters 7see map1 ,fig4 #e;,b74 ,certain high areas such as ,mount ,philo1 ,pease ,mountain and ,cobble ,hill show lake-level features along their sides which prove that these areas were islands rising above the level of this past lake4 ,if you visit ,mt4 ,philo ,state ,park1 located approximately #aa miles north of ,vergennes1 one of these lake-level features1 a wave-cut terrace1 can be seen at an elevation of #ede feet and on the south side of the hill 7at the level of the second reverse turn in your trip to the summit area74#i ,illustration3 ,,figure #e ,,early ,,coveville ,,maximum ,,coveville ,illustration3 ,figure #f4 ,looking west from the top of ,mount ,philo ,state ,park4 ,the ,adirondack ,mountains are on the skyline1 ,lake ,champlain in middle background and the ,champlain ,lowlands stretch from ,lake ,champlain to the base of ,mount ,philo4 ,illustration3 ,,figure #g ,,fort ,,ann ,,maximum ,,marine ,,maximum ,shortly after ,coveville ,lake ,vermont reached its maximum size 7see map1 ,fig4 #e;,b71 a southern gorge-outlet was formed at an elevation lower than the previous ,coveville outlet in the vicinity of ,fort ,ann1 ,new ,york 7,fort ,ann is located approximately #h miles south of the present southern extremity of ,lake ,champlain74 ,the level of ,lake ,vermont's water dropped to the new ,fort ,ann ,stage 7see map1 ,fig4 #g;,a74 ,evidence for this new lake level is seen on the slopes of ,mt4 ,philo1 ,snake ,mountain and ,cobble ,hill4 ,these lake-level features are parallel to and found #ajj feet below those of the ,coveville ,stage4 ,these parallel features1 then1 indicate that very little1 if any1 tilting of the earth's crust had taken place between the ,coveville and ,fort ,ann lake stages4 ,illustration3 ,figure #h4 ,beach and clay banks exposed along the ,lake ,champlain portion of ,button ,bay ,state ,park4 ,this view is toward the northwest and includes a major portion of the ,park's lake frontage4 ,photo by ,robert ,b4 ,williams4 ,this ,champlain ice lobe continued to melt and retreat toward the ,canadian border and beyond4 ,as the glacial front approached the ,st4 ,lawrence valley1 fresh water from ,lake ,vermont began to seep through the retreating ice lobe and into the marine waters which filled the ,st4 ,lawrence area4 ,several shoreline 7lake-level7 features are found at different elevations below the ,fort ,ann ,stage of ,lake ,vermont and attest to a slow lowering of the lake level by the escape of fresh water to the north4 ,the conspicuous clays of ,button ,bay ,state ,park were deposited during the next episode in the history of the ,champlain ,valley1 a development heralded by continued retreat of the ice lobe and contact with the ,st4 ,lawrence marine waters4 ,let's take a look at the clays so well displayed along the ,button ,bay ,state ,park beach and see if we can piece together their history4 ,,the ,,clays ,,of ,,button ,,bay ,,state ,,park ,the best location in the park for a good look at the clays which cover the entire ,park area is along the lake beach 7see ,figs4 #d and #h74 ,the bank averages #bc feet in height measured from the beach to the top of the bank4 ,the width of the beach varies seasonally and during storms as the water level of ,lake ,champlain fluctuates 7see ,figs4 #d and #h74 ,a walk along the beach will reveal some interesting facts about the composition of the beach and the adjacent clay banks4 ,one cannot help observing the scarcity of sand#aj on the beach4 ,the only adjacent material to build this beach is clay1 which here contains a small quantity of sand and some concretions containing lime4 ,the sickle shape of ,button ,bay keeps most foreign sand from the beach4 ,the small patches of sand present soon give way to blue clay#aa which1 in many places1 forms the base of the beach4 ,this blue clay can also be seen in the base of the bank in the southern portion of the ,park1 where it underlies and is therefore older than the brown clay4#ab ,actually very little of the blue clay is exposed in the ,park4 ,from other locations along the shore of ,lake ,champlain and in the more inland areas of the ,champlain ,lowlands geologists have found many clues to help our understanding of its history4 ,illustration3 ,figure #i;,a4 ,view of the ,brown ,clay at the base of the clay-cliff1 ,button ,bay ,state ,park4 ,for scale1 note the small ballpoint pen resting on top of ledge 7left of center74 ,a close-up view of this ledge 7pen in same location7 is seen in ,figure #aj4 ,illustration3 ,figure #i;,b4 ,close-up view showing general characteristics of the ,brown ,clay4 ,notice the vertical cracks in the clay4 ,these cracks or joints are very common in the clays of this ,state ,park4 ,in ,august #ahdi the incomplete skeleton of a whale#ac was found in a railroad cut being excavated for the ,rutland and ,burlington ,railroad4 ,this cut was located approximately #ab miles south of ,burlington and a mile east of ,lake ,champlain4 ,the significant fact about this 8find0 is that these bones were found in the same type of blue clay that occurs at the beach in ,button ,bay ,state ,park4 ,clam and oyster shells 7,pelecypods7 were found in association with the whale bones4 ,these pelecypod shells#ad and the whale bones show that these animals lived and died in cold marine waters4 ,lake ,champlain today is a fresh-water lake and the fish and other organisms in it are those of fresh1 not salty water4 ,yet the blue clays 7and we are soon to learn1 the brown clays7 hold evidence proving the existence of sea water in an area where a fresh-water lake is found today4 ,can this be explained8 ,the brown clay forms most of the ,park's clay banks 7see ,figs4 #i;,a and #i;,b 74 ,it can be examined easily by the visitor4 ,the bank is composed of clay and variable amounts of fine sand#ae in thin lens-shaped bodies4 ,the hard dry outer clay1 if rain has not just fallen1 of the upper #ae feet of the bank appears light brown or tan-white and commonly contains interspersed white and blue streaks4 ,in the section of the bank which was the object of detailed study1 two conspicuous convoluted beds#af were found1 one #e feet above the beach1 the other nearly #b feet above the first4 ,shells of pelecypods#ag occur at two and perhaps three levels within the bank4 ,they can be seen easily in many slumped clay bodies along the beach 7see ,fig4 #aj1 in which the shells are mainly ,macoma and ,saxicava74 ,these shells once belonged to living animals whose very close relatives and identical younger generations are found living today in cold ,arctic waters4 ,brown clays were deposited in a marine ,champlain ,sea4 ,how did these marine waters get into the ,champlain ,valley8 ,illustration3 ,figure #aj4 ,close-up view showing the pelecypod 7clam7 shells which occur within the ,brown ,clays4 ,note small ,ballpoint pen for scale4 ,these shells tell us of the marine origin for these clays4 ,the pelecypods here are ,saxicava and ,macoma4 ,remember from the previous discussion of ,lake ,vermont that as the ,champlain ice lobe retreated into ,canada1 fresh water from ,lake ,vermont began to seep through the ice lobe into the ,st4 ,lawrence ,valley4 ,this seepage caused a gradual lowering of the ,lake ,vermont water-level until the lake reached a stage lower than the marine waters of the ,st4 ,lawrence ,sea4 ,soon the sea water began to flood ,lake ,vermont and true marine conditions were reached4 ,these marine waters reached as far south as ,whitehall1 ,new ,york1 which is located near the southern end of present-day ,lake ,champlain4 ,the maximum area covered by the ,champlain ,sea did not equal the greatest size attained by the fresh waters of ,lake ,vermont4 ,for instance1 the sea did not extend as far east as the ,green ,mountains except in the very northernmost region of ,vermont4 ,in the vicinity of ,button ,bay ,state ,park these waters extended less than a mile east of ,vergennes1 and the towns of ,middlebury1 ,hinesburg and ,charlotte would have been entirely above water 7see map1 ,fig4 #g;,b74 ,it has been postulated that marine waters extended throughout the length of the ,champlain ,valley and into the ,hudson ,valley1 forming a continuous strip of marine water from the ,gulf of ,st4 ,lawrence to the ,atlantic ,ocean at the mouth of the ,hudson ,river4 ,if this were true1 ,new ,england would have been an island only a few years ago 7geologically speaking74 ,the weight of evidence available today does not support the prior existence of this connecting ribbon of sea water4 ,today ,lake ,champlain contains fresh water again1 and the marine conditions have retreated back into the ,gulf of ,st4 ,lawrence4 ,what happened to permit a return to fresh water conditions8 ,the lakes and lake-stages discussed are known from the presence of various shoreline features1 most of which are now 8high and dry40 ,each lake or lake-stage has its own set of lake-level features4 ,an interesting fact emerges from a study of any one former lake4 ,the present elevation above sea level of delimiting lake-level features is not the same throughout4 ,to explain this more fully1 the present elevation of those features formed when the ,champlain ,sea was at its maximum extent will be examined4 ,at ,shelburne ,falls the present elevation of these features is #cjj feet1 at ,st4 ,albans #ddj feet1 and at ,roxton1 ,quebec1 #eeb feet4 ,it will be noted that proceeding from south 7,shelburne ,falls7 to north 7,roxton7 a difference of over #bej feet is found between features formed at an identical time in the past4 ,the water in any lake is practically level4 ,it therefore follows that the present #cjj1 #ddj and #eeb foot elevations of the shoreline features are the result of subsequent tilting of the earth's surface4 ,perhaps the following reference to the water level of present ,lake ,champlain will help in your understanding of this tilting4 ,the present-day average level of the water in ,lake ,champlain is about #ib feet above the level of the ,atlantic ,ocean4 ,this water-level elevation is constant throughout the extent of ,lake ,champlain and is not1 say1 #ib feet at ,button ,bay and #aib feet at ,burlington4 ,again1 the only way that features demonstrating past lake margins or levels could1 for any one lake or lake-stage1 now exist at different elevations would be if some earth movements took place after the formation of the features1 resulting in a change from their original elevations4 ,the earth's crust has been tilted1 higher in the north than in the south1 during recent times4 ,this tilting provides the clue to the formation of present-day ,lake ,champlain4 ,major tilting took place after the maximum marine invasion4 ,tilting continued1 at a decreasing rate1 perhaps1 to the present day4 ,this tilting1 with greater relative rise in the northwest1 eventually reached a point where marine waters were excluded from the ,champlain ,basin4 ,fresh water slowly diluted the salty marine water4 ,the lake gathered more and more fresh water through rain and melting snow1 and a new outlet formed in the north1 in the approximate location of the present ,richelieu ,river4 ,the area of ,lake ,champlain slowly increased to its present size1 and the clays which once formed lake and sea bottom became the 8hard earth0 of the ,champlain ,lowlands4 ,continued tilting caused flooding of the streams1 especially in the southern portion of ,lake ,champlain1 such as the now swampy ,otter ,creek and its tributary ,dead ,creek 7see map1 ,fig4 #b74 ,this concludes the story of the ,park clays4 ,from the rocks which crop out within a short walking distance of ,button ,bay ,state ,park a much older segment of geologic history can be studied4 ,,the ,,older ,,rocks ,the rocks which underlie ,button ,bay ,state ,park can be seen along the small creek which is located just south of the ,park4 ,it is suggested that the visitor walk southward 7to the right if approaching the road from the lake front7 along the main park road until the first culvert beneath the road is reached4 ,looking down the creekbed toward the lake1 one can readily see the older rocks 7see ,a1 ,figure #aa74 ,fossils#ah are found in these tilted rocks which tilt or dip toward the northeast and 8strike0 northwestward4 ,fossils date the rocks underlying ,button ,bay ,state ,park as ,middle ,ordovician4#ai ,the most abundant fossil is a trilobite1 ,triarthrus1 but1 even this ancient arthropod#bj is not easily found in these limestones and limy shales4 ,a sketch of ,triarthrus 7that portion found fossilized7 appears in ,plate #a4 ,these rocks containing ,triarthrus beckii belong to the ,stony ,point formation and are of late ,sherman ,fall or ,denmarkian age4 ,one of the jobs of the geologist is to reconstruct the paleogeography 7ancient geography7 of a region4 ,the different kinds of rocks present and their distribution patterns1 together with the types of fossil plants and animals found1 tell the geologist of past lands and seas1 warm and cold climates4 ,the rocks of the ,stony ,point formation 7the rocks which underlie most of the ,park7 tell of warm marine waters1 a past sea1 bordered by relatively low land areas4 ,the fossils contained in the ,stony ,point formation attest to the presence of relatively shallow marine waters4 ,the fact that these ,ordovician rocks are tilted and broken by faults proves that major earth movements#ba took place sometime after their lithification4 ,illustration3 ,,plate #a #a;,a1 ,b1 ,c2 ,maclurites magnus ,lesueur 7,x #j4e74 ,lower1 upper and side views4 ,crown ,point limestone4 ,,gastropod 7snail74 #b2 ,triarthrus beckii ,green 7,x #c74 ,top view of central part of head region4 ,stony ,point shale4 ,,trilobite4 #c2 ,saxicava 7,x #c74 ,pleistocene marine clays4 ,,pelecypod4 #d2 ,macoma 7,x #c74 ,pleistocene marine clays4 ,,pelecypod4 #e;,a1 ,b2 ,rhinidictya 7,x #i and ,x #a74 ,orwell limestone4 ,,bryozoan4 #f;,a1 ,b1 ,c3 ,cryptolithus tesselatus ,green 7,x #b74 ,top1 side and front views4 ,glens ,falls limestone4 ,,trilobite4 #g2 ,rafinesquina4 ,internal view4 ,orwell and ,glens ,falls limestones4 ,,brachiopod4 ,illustration3 ,,figure #aa ,,geologic ,,map ,,older ,,rocks 7fault7 ,,crown ,,point ,,limestone ,,chazy 7,,valcour87 7,clay covered in most areas7 ,,orwell ,,limestone 7clay covered7 ,,glens ,,falls ,,limestone 7clay covered in most areas7 7fault7 ,,stony ,,point ,,formation 7clay covered in most areas7 ,,geology ,,north ,,of ,,park ,,boundary ,,adapted ,,from ,,charles ,w4 ,,welby--#aifa ,from the north boundary of the ,park and along the ,lake ,champlain shoreline older and older ,ordovician rocks are encountered4#bb ,the rocks 7see geologic map1 ,fig4 #aa71 primarily tilted marine limestones1 display a variety of fossils1 some of which are illustrated in ,plate #a4 ,figure #ab is a view of the west side of ,button ,island showing an #ah-;inch thick reefy zone in the ,orwell limestone4 ,the reefy zone is composed largely of tumbled heads of colonial corals and stromatoporoids4 ,a selected list of reference books and articles1 some of which contain plates picturing ,ordovician fossils1 is found at the end of this section4 ,ordovician and older rocks were lifted1 folded and faulted during the ,taconic ,disturbance4 ,dramatic evidence for this period of crustal instability is seen in the ,champlain ,thrust1 a major series of faults which can be seen east of ,button ,bay ,state ,park4 ,the evidence for such a fault system1 which is more fully discussed in another pamphlet1 is readily seen on ,mount ,philo where older ,cambrian rocks have overridden 7been thrust over7 younger ,ordovician ones4 ,as time passed in the ,button ,bay region younger and younger sediments were deposited over the top of folded and eroded ,ordovician rocks4 ,these sediments became rock and in turn slowly broke into fragments which were transported to other areas where they were deposited again as sediments4 ,the glaciers passed over1 leaving their rock debris behind as they wasted northward4 ,marine clays were slowly deposited from the waters of the ,champlain ,sea4 ,today only the marine clays resting on the beveled edges of ,middle ,ordovician rocks can be seen in the ,park4 ,the history of the earth is open for all to read4 ,button ,bay ,state ,park can tell us only the history which is recorded in its clays and underlying rocks4 ,as we have seen1 there are certain giant geologic time gaps in the ,park area1 but many of these do not exist in other places and in other ,parks4 ,if this pamphlet has stimulated an interest in filling in these time gaps through your study of rocks in other places1 then it has fulfilled its purpose4 ,the present interest in ,space demands a good long look at the ,planet ,earth4 ,good ,hunting6 ,illustration3 ,figure #ab4 ,bedded ,orwell limestone on open-lake side of ,button ,island1 showing patches of stromatoporoids and colonial corals 7white areas74 ,photo by ,c4 ,w4 ,welby4 ,,suggested ,,reading ,historical ,geology1 by ,carl ,o4 ,dunbar1 ,john ,wiley ,sons1 ,inc41 ,new ,york1 #aifj4 ,good general treatment of what the rocks can and do tell geologists about the history of the ,earth4 ,handbook of ,paleontology for ,beginners and ,amateurs1 ,part #a1 ,the ,fossils1 by ,winifred ,goldring1 ,new ,york ,state ,museum ,handbook #i 7obtainable from3 ,paleontological ,research ,institution1 #aij ,dearborn ,place1 ,ithaca1 ,n4 ,y474 ,fossils1 ,an ,introduction to ,prehistoric ,life1 by ,w4 ,h4 ,matthews ,,iii1 #aifb1 ,barnes and ,noble1 ,inc41 ,new ,york4 ,earth history and paleontology1 a general guide for the amateur collector4 ,bedrock ,geology of the ,central ,champlain ,valley of ,vermont1 by ,charles ,w4 ,welby1 #aifa4 ,vermont ,geological ,survey ,bulletin #ad4 ,standard work for the geology in the region of ,button ,bay ,state ,park4 ,paleontology of the ,champlain ,basin in ,vermont1 by ,c4 ,w4 ,welby1 ,vermont ,geology ,series1 ,vermont ,geological ,survey4 ,a treatise on the paleontology of the ,champlain ,basin designed for the amateur4 ,in press4 ,index ,fossils of ,north ,america1 by ,h4 ,w4 ,shimer and ,r4 ,r4 ,shrock1 #aidd1 ,john ,wiley ,sons1 ,inc41 ,new ,york4 ,contains many plates depicting several of the fossils found in and adjacent to ,button ,bay ,state ,park4 ,footnotes #a,most of the information for this section was graciously supplied by ,clara ,e4 ,follette1 ,librarian and ,museum ,director1 ,vermont ,historical ,society1 ,montpelier1 ,vermont1 in a letter to the author dated ,april #bf1 #aifa4 #b8,the governors 7and other gentlemen7 appear to have included ,sir ,henry ,moore1 ,governor of ,new ,york1 ,general ,carleton1 ,governor of ,quebec1 ,brig4 ,general ,philip ,schuyler 7and ,adolphus ,benzel1 map maker74 ,the activities of these persons on the lake at that time were evidently concerned with making observations1 primarily to determine boundaries40 #c,seely1 ,h4 ,m41 #aiaj1 ,preliminary ,report of the ,geology of ,addison ,county2 ,vermont ,state ,geologist1 #gth ,biennial ,report1 p4 #beg-cae4 #d;,concretions consist of concentrations of certain chemical elements and compounds into regular or irregular masses4 ,many times the center of a concretion consists of a definite nucleus such as a grain of sand or shell fragment4 ,for a general idea of the size and shape of the concretions seen along the ,button ,bay ,state ,park beach see ,fig4 #c and cover picture4 #e,these clays were deposited from marine waters which flooded the ,champlain ,valley after the final retreat of the glaciers which completely covered ,new ,england during the 8,great ,ice ,age0 or ,pleistocene ,epoch4 ,the ,pleistocene ,epoch began approximately one million years ago and if the age of the ,earth is considered to be five billion 7#e1jjj million7 years1 then1 the clays do record recent geologic history4 #f;,as the weight of the ice was removed from the ,hudson ,valley region the earth's crust1 in way of adjustment to this removal of weight1 slowly began to rise4 ,some geologists doubt whether the removal of ice weight alone can account for the crustal rise and propose other internal forces as partly or wholly responsible4 ,the fact remains that the earth's crust did rise in this area4 #g;,as the ice retreated1 a succession of lakes formed in the ,champlain ,valley4 ,each lake had a level waterline during its history and certain lakeshore features formed1 as they do in any present-day lake1 with respect to each past level water-line4 ,for example1 ridges of sand and gravel were heaped along the shoreline by lake waves4 ,wave-cut and wave-built flat areas or terraces were formed along the margins of lakes or along the sides of islands within a lake4 ,streams entering a lake built deltas by depositing materials it had carried down from the surrounding highlands4 #h;,elevation is measured in feet above the mean sea level of today1 with mean sea level being zero feet4 #i;,a most impressive view can be gained from any one of the several lookout points at the summit level of ,mt4 ,philo4 ,looking to the west1 toward ,lake ,champlain1 and south in the direction of ,vergennes and ,button ,bay ,state ,park1 a three dimensional view of an old lake 7,lake ,vermont7 can be seen4 ,in this view the present ,lake ,champlain ,lowlands represent the old lake bottom and the numerous hills rising above this ,lowland were once islands or near-islands which dotted the surface of the lake4 ,it takes very little imagination to place yourself on the 8island of ,mt4 ,philo0 and to visualize a boat tied to a dock just below the rocky cliffs on which you stand4 ,a trip to ,mt4 ,philo with its spectacular view of the ,champlain ,lowlands 7see ,fig4 #f7 is recommended4 #aj,one word of caution1 the ,park authorities may import sand from other areas of ,vermont to improve the swimming facilities along the beach4 ,in this case1 the abundant sand on the beach will not constitute the 8natural beach composition0 for ,button ,bay ,state ,park4 #aa,the blue color is due to the presence of ferrous iron 7bivalent iron7 together with iron compounds in which iron has its higher chemical valence 7ferric iron74 ,this ferrous iron demands a chemically reducing environment for its formation and indicates that the clays were deposited in a shallow sea or that they remained for some time beneath a stable water-table4 ,they contained a fair quantity of decaying organic material4 #ab,the brown color is due to the presence of the ferric hydroxide1 goethite 7,h,fe,o74 #ac,this fossil whale is scientifically known as ,delphinapterus vermontanus 7,thompson74 #ad,the pelecypods found are scientifically known as ,macoma groenlandica and ,saxicava rugosa4 #ae,the size limits of sand lie between #bmm in diameter 7largest7 and _/mm in diameter 7smallest74 ,two millimeters 7mm7 equals approximately _/ inches4 ,fine sand would fall between mm and mm in diameter4 #af;,convolute beds show their layers thrown into a series of folds 7some quite irregular7 which result from the pressing weight of overlying sediments on highly plastic layers beneath4 ,some feel that these folds were the result of actual flowage of the layers in the direction of their tilt1 and others credit the distorted bedding to the pressing weight of large boulders4 ,these dragged across the layers while still frozen to overriding glacial ice4 #ag,the author noted both ,macoma groenlandica and ,saxicava rugosa 7see ,fig4 #aj and ,plate #a1 ,sketches #c and #d74 #ah;,fossils are the preserved evidence of past life 7animal or plant7 as found in rocks or sediments1 for example1 the clams found in the clays4 ,they may be direct evidence1 such as the actual shells or mineralogically replaced shells of long-dead animals2 or indirect evidence1 such as the tracks or trails of animals now preserved in rocks4 #ai;,geologic time is divided into four ,eras which are designated from oldest to youngest3 ,precambrian1 ,paleozoic1 ,mesozoic1 and ,cenozoic4 ,each of these ,eras is divided into geologic ,periods of time4 ,the ,ordovician ,period is next to the oldest ,period of the ,paleozoic ,era4 ,this ,period began some #dbj million years ago1 and ended approximately #cfj million years ago4 #bj,present ,arthropods include the insects1 spiders and crabs4 ,arthropods1 which are invertebrate animals 7without backbones71 are characterized by jointed legs1 chitinous outer covering and segmented body parts4 ,trilobites were very numerous in the early ,paleozoic seas1 but became extinct before the end of that ,era4 #ba,the folding and the faulting of the ,ordovician rocks took place sometime between the closing phases of the ,ordovician ,period and the beginning of late ,silurian time 7between #cfj and #ccj million years ago74 ,usually these earth movements are ascribed to the ,taconic ,disturbance which took place at the end of the ,ordovician ,period4 #bb;,a walk along the beach in the direction of ,button ,island or 8sickle point0 7west and then south from the northern boundary of the ,park7 traverses the following geologic formations3 the ,glens ,falls limestone which can be seen on ,ship ,point 7actually an island off the northern end of the ,park72 the ,orwell limestone1 seen on ,button ,island2 the ,valcour formation which makes up 8sickle point02 and the ,crown ,point limestone which is found on the ,basin ,harbor-side of 8sickle point40 ,these rock units belong to the ,chazyan ,stage 7,crown ,point limestone and ,valcour formation7 and the next younger ,mohawkian ,stage 7,orwell and ,glens ,falls limestones7 of the ,middle ,ordovician ,champlainian ,series4 ,transcriber's ,notes --,silently corrected a few typos4 --,retained publication information from the printed edition3 this e,book is public-domain in the country of publication4 --,in the text versions only1 text in italics is delimited by underscores4