,illustration3 ,cover3 ,looking southward along ,groton ,pond from near ,stillwater ,brook4 ,,the ,,geology ,,of ,,groton ,,state ,,forest ,by ,,robert ,a4 ,,christman ,,department ,,of ,,forests ,,and ,,parks ,perry ,h4 ,merrill1 ,director ,,vermont ,,development ,,commission ,,vermont ,,geological ,,survey ,charles ,g4 ,doll1 ,state ,geologist #aief ,,geology ,,of ,,groton ,,state ,,forest ,by ,,robert ,a4 ,,christman ,,introduction ,geology is the study of the history of the earth as recorded in its rocks4 ,this study explains why certain types of rocks and minerals occur at one place and not another1 why the forms of the land differ from one region to another1 and why particular animal and plant remains are sometimes preserved as fossils in certain kinds of rocks4 ,the professional geologist makes these studies his business2 the amateur finds these studies a fascinating hobby2 but the uninitiated person misses much of the pleasure of travel4 ,anyone who notices the difference between rocks or terrains and wonders 8why801 has a potential for geology4 ,many fall into this class and it is for them that this booklet has been written4 ,it is hoped that with its aid1 the traveler or vacationer may come to know something about the geology of ,groton ,state ,forest4 ,the author is confident that those who come into the habit of observing nature and the world around them will find more meaning in life itself4 ,in any case1 those traveling with children may find answers to some of their questions about minerals1 rocks and mountains4 ,groton ,state ,forest is not a geologist's paradise--as compared to ,yellowstone ,park or the ,grand ,canyon--but it does contain interesting rocks and land forms which can be explained geologically4 ,in keeping with the calm1 subdued and mature atmosphere of the ,vermont countryside1 the geology is unobtrusive4 ,there are few jutting cliffs or bare rock exposures2 all is mantled with vegetation4 ,if this vegetation could be stripped away--admittedly1 a postulation that would destroy the wilderness and charm that belongs to ,groton--boulders and gravelly glacial deposits would be seen to fill the valleys4 ,if in turn these boulders and the soil could be stripped away1 a continuous floor of rock would be exposed4 ,this would be a geologist's paradise--square miles of bare rock would be available for study4 ,however1 lacking the magic wand to perform this feat1 we must be satisfied to glean what information we can from the existing rock exposures4 ,to use a pun1 it can be said that almost all the rocks found at ,groton ,state ,forest can be taken for granite4 ,as well as has been determined1 all the underlying rock is granite#a and most of the boulders deposited by glaciers of the last ice age are the same type of granite4 ,to avoid confusion in describing these rocks1 the discussion has been divided into two parts3 the first deals with the granite of the bedrock1 and the second deals with the glaciation of the area and the deposits resulting from it4 ,a third section describes the geology in some of the nearby areas4 ,,granite ,,and ,,related ,,rocks ,occurrence of the granite ,ledges of light-colored granite occur at the summits of most of the mountains and hills in the ,state ,forest area and are found occasionally at lower elevations4 ,they are conspicuous on ,owlshead1 ,silver ,ledge1 ,little ,deer1 ,big ,deer1 ,niggerhead and ,spicer ,mountains2 smaller ledges also occur on ,kettle1 and ,little ,spruce mountains1 ,hardwood ,ridge and the low hills east of ,groton ,pond4 ,at lower elevations1 granite is found at the outlet of ,groton ,pond1 along the railroad tracks west of ,groton ,pond and at ,stillwater ,brook1 along ,osmore brook and at several other minor locations4 ,these locations are shown diagrammatically on the map by a black dot4 ,these dots indicate where the granite occurs but nothing about the extent of the exposure4 ,if every location of exposed rock were marked with a dot1 certain parts of the map1 for instance1 the west side of ,niggerhead1 would be solid black and the contour lines which show the elevation would be obscured completely4 ,all these rocks are presumably part of one large mass of granite which extends deep below the surface of the earth4 ,most of this body of granite is hidden by the soil and bouldery glacial deposits1 so that its exact areal extent is not known4 ,it appears likely that it extends to the southwest to the vicinity of ,east ,barre4 ,description of the granite ,the granite found at ,groton ,state ,forest is a gray to white1 medium-grained rock with the mineral grains all about the same size4 ,surfaces exposed to weathering are generally darker in color and frequently are covered with scales of dark colored lichen4 ,if the rock is broken to reveal an unaltered surface close examination will disclose individual mineral grains of mica1 feldspar and quartz4 ,mica occurs as very small plates which appear either white or colorless1 called muscovite1 or as black shiny plates called biotite4 ,the feldspar1 which is the most abundant mineral in the granite1 has a chalky white appearance and may occur as tabular grains which reflect light from their flat surfaces when held in the proper position4 ,quartz1 which contains only silicon and oxygen1 the two most common elements in the earth's crust1 is a transparent1 glassy mineral which has no flat surfaces4 ,it may appear gray because one can look down into the glassy mineral where there is no light source4 ,a specimen of granite from ,owlshead was studied with a microscope after it had been cut and ground to a thickness of only #j4jc millimeters4 ,many minerals1 which ordinarily appear to be opaque1 are transparent when ground this thin4 ,by their various optical properties1 the different minerals can be identified and the composition of the rock can be determined4 ,figure #a shows a photograph1 taken through a microscope1 of one of these thin sections of granite4 ,by careful examination of the thin section and by measuring the areal extent of the different minerals present1 the rock was determined to contain1 by volume1 #ce percent quartz1 #fj percent feldspar 7in proportions of #be percent microcline feldspar1 ,k,al,si,o and #ce percent plagioclase feldspar1 ,na,al,si,o7 and #e percent mica 7in proportions of #d percent biotite and #a percent muscovite74 ,although it is a member of the granite family1 this rock should1 in strict terminology1 be called a quartz monzonite rather than a granite to indicate more precisely the mineral composition4 ,because of slight differences in composition1 granite from the same body may elsewhere be correctly called granodiorite1 quartz diorite or granite proper1 depending on the relative amounts of the two feldspars and quartz4 ,in this report these close distinctions have not been made and the rock is simply called granite4 ,cracks in the granite ,two kinds of natural breaks1 or cracks1 occur in the granite in the ,state ,forest area4 ,joints are breaks which occur along plane surfaces and exfoliation is the name given to the breakage along curved surfaces related to the exposure of the rock4 ,granite1 as contrasted with other rocks1 is characterized by its uniformity of texture and massiveness1 so that any cracks present are conspicuous4 ,illustration3 ,figure #a4 ,photomicrograph of a thin section of granite from ,owlshead ,mountain4 ,the mineral with the grid pattern 7upper left7 is a feldspar named microcline which has the composition of ,k,al,si,o4 ,the one with the indistinct striped pattern 7lower center7 is a feldspar named plagioclase1 variety oligoclase1 which has the composition of approximately ,na,al,si,o4 ,the patterns for these minerals result from different portions of the same mineral grain having different orientations1 called twinning1 so as to give a different optical appearance4 ,the clear white mineral 7right center7 is quartz4 ,the dark gray mineral with the fine lines 7upper center7 is biotite and the smaller1 lighter-colored1 elongate mineral to the right of the biotite is muscovite4 ,the other minerals are feldspar and quartz in different orientations4 ,the actual diameter of the clear white quartz grain 7right center7 is about four-tenths of a millimeter so that the photograph is a magnification of about one hundred4 ,joints are more conspicuous of the two types1 and typically belong to a general system so that at a given location they tend to be parallel4 ,on top of ,owlshead1 for example1 the most prominent joints trend ,n4#be,w4 7read3 ,north twenty-five degrees to the west7 with dips#b that are vertical or dipping steeply to the southwest4 ,another set of joints trends ,n4#aj;,e4 with dips that are vertical or dipping steeply to the southwest4 ,joints represent the breakage of the rock due to stress and strain4 ,some joints result from tensional forces set up within the rock itself by contraction due to cooling of the originally hot solidified rock4 ,other joints result from larger-scale forces within the earth's crust which cause earthquakes and general movement of land masses4 ,an exhaustive study of all the rocks in a large area would be required to determine conclusively the origin of the joints on ,owlshead4 ,in addition to the nearly vertical joints1 a third set of nearly horizontal joints may be observed on cliffs4 ,these joints are called sheeting and apparently are related to the depth from a former topographic surface which existed at the time the sheeting originated4 ,the vertical joints and sheeting are important qualities of a rock to be considered in choosing a rock for commercial quarrying4 ,not only do these factors effect the ease of quarrying1 but they also determine the amount of waste material which would have to be removed and discarded because of poor size and shape4 ,exfoliation is the term for breakage due to the disintegration caused by decomposition of the rock on surfaces exposed to the weather4 ,it is characterized by the scaling off of concentric shells of altered rock to produce a convex surface4 ,rocks showing exfoliation surfaces are not common at ,groton4 ,one of the best developed exfoliation surfaces1 illustrated in ,figure #b1 occurs at the base of the cliffs on the south side of ,owlshead ,mountain4 ,once joints have formed1 they are enlarged by weathering4 ,in particular1 rocks are pushed apart by a 8frost wedging40 ,when water freezes it expands by about one-tenth of its volume4 ,if it is confined it may exert a pressure of as much as #ach tons per square foot4 ,in this manner1 huge blocks may be pushed apart4 ,if they are at the edge of a cliff1 or part of the cliff itself1 they may eventually break off and fall to the slope below4 ,the accumulation of broken rock at the base of a cliff is called talus4 ,origin and age of the granite ,the granite originated in the interior of the earth many million years ago as a molten mass1 called magma4 ,this magma moved upward through the earth's crust by a process of melting the pre-existing rock or by forcefully pushing it aside4 ,when it reached its present position it became cooler and minerals began to crystallize out4 ,however1 as is shown in ,figure #c1 it is important to understand that the surface of the land was not in its present position and that the magma actually cooled beneath a considerable thickness of other rocks4 ,these overlying rocks1 now gone1 acted as an insulator and prevented the magma from cooling too quickly4 ,if the magma had risen through these rocks and reached their upper surface1 it would have formed a lava flow similar to those of present-day volcanoes and would have cooled much more rapidly4 ,rocks formed near the surface are characterized either by being fine-grained without visible crystals or by having a few large crystals in a fine-grained matrix2 they never have a uniformly1 medium-to-coarse-grained texture4 ,thus1 the texture of the granite at ,groton ,state ,forest proves that it cooled slowly and indicates that1 at the time of cooling1 the granite was not at the surface4 ,this is a reasonable postulation because studies of the regional geology indicate that a large amount of rock has been removed from this area by erosion through the long periods of geologic time4 ,illustration3 ,figure #b4 ,exfoliation surface on the south side of ,owlshead ,mountain4 ,joints1 of the sheeting type1 are visible in the granite cliff4 ,the decomposition of the granite by weathering in the niches has resulted in small patches of soil4 ,the boy in the upper right gives the scale4 ,illustration3 ,figure #c4 ,sequence of events at ,groton ,state ,forest shown diagrammatically4 ,illustration3 ,a4 ,the ,waits ,river ,formation and other younger formations are deposited from a shallow sea during ,ordovician time4 ,,younger ,,formations ,,waits ,,river ,,formation ,illustration3 ,b4 ,the sedimentary rocks are folded and metamorphosed and the granite is intruded into the older rocks and crystallizes during ,devonian time4 ,,waits ,,river ,,formation ,,granite ,illustration3 ,c4 ,erosion removes much of the rock from the area4 ,,granite ,illustration3 ,d4 ,during the ice age1 continental glaciers move over the land and erosion by the ice forms ,owlshead ,mountain and the basin for ,groton ,pond4 ,,ice ,,granite ,illustration3 ,e4 ,present topography1 exaggerated4 ,,owlshead ,,mountain ,,ricker ,,mills ,evidence that the granite was emplaced into the older rocks of the earth's crust can be seen at certain locations outside of the ,state ,forest4 ,at ,ricker ,mills1 for example1 narrow bodies of granite can be seen cross cutting the older rocks4 ,a fuller description of the geology at ,ricker ,mills is given in a later section of this report4 ,another type of evidence showing that the granite came into older rocks is found in the occurrence of fragments of older rock incorporated into the granite4 ,these are called inclusions and represent broken pieces of older rock which were enveloped by the granite4 ,inclusions are like peach slices in jello in that the surrounding material solidified after they were dropped in4 ,inclusions were observed in rocks on top of ,kettle and ,jerry ,lund ,mountains4 ,near the covered picnic shelter at ,ricker ,pond1 one of the large granite boulders deposited by the glacier contains inclusions4 ,although this boulder has been moved from its original occurrence1 it probably has not moved far as it is composed of the white granite which is typical of the area4 ,it is cut by several pegmatitic dikes4 ,the most interesting feature is the occurrence of inclusions of elongate1 layered bands of older rocks of gray to dark gray schist4#c ,these relations are shown in the sketch of this boulder in ,figure #d4 ,a careful examination of the schist inclusions reveals that they contain small plates of biotite in a fine matrix of quartz and more mica4 ,the contact between the schist and granite is gradational at places because when the rock was formed the hot molten granite was in the process of melting the solid schist4 ,the schist resembles the rock which occurred in this area before the granite was intruded and which occurs in nearby areas where no granite is exposed4 ,older rocks of somewhat similar appearance can be seen at ,ricker ,mills and on top of ,jerry ,lund ,mountain4 ,the composition of the granite at ,groton ,state ,forest is nearly the same as that which occurs throughout this region of ,vermont4 ,incomplete mapping suggests that the granite at ,groton is part of a large mass which extends to the southwest to the vicinity of ,east ,barre4 ,undoubtedly all the granitic rocks of this region are related although they are not continuous at the surface4 ,they were all emplaced at about the same time following a mountain-building episode in which the older rocks were folded and metamorphosed4 ,on the geologic time scale1 the granites were emplaced near the end of the ,devonian period which is estimated to be more than #cjj million years ago4 ,illustration3 ,figure #d4 ,sketch of boulder of granite containing pegmatite band and schist inclusions at picnic area at ,ricker ,pond4 ,,granite ,,pegmatite ,,schist ,aplite and pegmatite ,two other types of igneous rocks called aplite and pegmatite occur sparingly in ,groton ,state ,forest4 ,both of these are productions of crystallization of residual fluids or late stage magma related to the granite4 ,these were emplaced along cracks or planes of weakness in the granite after the granite had solidified4 ,when viewed from the surface the aplite or pegmatite generally appear as bands cutting through the granite4 ,however1 when the third-dimension is considered it is easily realized that they are tabular or sheet-like in shape4 ,igneous rock masses having these dimensions are called dikes4 ,at ,groton most of the dikes are nearly vertical with a thickness ranging from less than an inch to more than several feet and extending for considerable distances4 ,on ,owlshead1 one of these dikes is nearly three feet thick4 ,the extent of these dikes is not known because they are only partly exposed1 in that they extend beyond the limited areas of rock exposure4 ,illustration3 ,,groton ,,state ,,forest ,,drew ,,mtn ,,niggerhead ,,mtn ,,blake ,,hill ,,niggerhead ,,brook ,,kettle ,,mtn ,,spicer ,,mtn ,,owlshead ,,mtn ,,kettle ,,pond ,,stillwater ,,bk4 ,,hardwood ,,ridge ,,beaver ,,brook ,,silver ,,ledge ,,little ,,spruce ,,mtn ,,peacham ,,pond ,,deer ,,mtn ,,devil',s ,,hill ,,peacham ,,bog ,,little ,,deer ,,mtn ,,osmore ,,bk4 ,,coldwater ,,bk4 ,,groton ,,pond ,,jerry ,,lund ,,mtn ,,ricker ,,pond ,,ricker ,,mills ,,explanation ,,granite ,,exposures ,,schist ,,exposures ,,trail ,,railroad ,,swampy ,,areas ,,contour ,,line ,,with ,,elevation ,,contour ,,interval ,,is #ajj ,,feet ,,topography ,,from ,u4 ,s4 ,,geological ,,survey ,,maps ,,by ,,robert ,,christman ,the pegmatite dikes are coarse-grained1 in some cases consisting of individual mineral grains as much as two to four inches in diameter4 ,the mineral composition of the pegmatites is nearly the same as the granite1 except that biotite is usually absent4 ,because of their larger grain size1 the minerals can be recognized more easily in pegmatites than in either granite or aplite4 ,quartz is glassy and breaks with smooth curved fractures4 ,feldspar is chalky white1 or pink1 and may occur as tabular crystals with straight-line contacts4 ,it tends to break along definite intersecting planes which can be seen in their reflecting position4 ,muscovite occurs as 8books0 of semi-transparent leaves4 ,the large 8books0 of muscovite are particularly interesting because of the fascinating fact that a mineral sheet can be split along a given planar direction into thinner and thinner sheets until they are too thin to handle4 ,theoretically the mineral might be split into sheets only as thick as one layer of atoms4 ,the ability of a mineral to break along definite planes is related to its atomic structure and is called cleavage4 ,the cleavage in mica is perfect1 whereas the cleavage in feldspar is only poorly developed1 and quartz does not possess cleavage at all4 ,the aplite dikes are composed of nearly the same minerals as granite except that the average grain size is smaller4 ,they are characterized by the absence of dark minerals and muscovite and by a high quartz content which gives the rock a 8sugary0 appearance4 ,most of the aplite dikes are less than six inches thick4 ,inasmuch as the pegmatite and aplite dikes both cut through the granite1 they both must be younger in age than the granite4 ,as is shown by the relations between these two types on ,owlshead 7reproduced in ,figure #e71 the pegmatite dike is younger because it cuts across the aplite dike4 ,this is the general age relationship for these dikes in this age4 ,illustration3 ,figure #e4 ,sketch showing aplite and pegmatite dikes in the granite on ,owlshead ,mountain4 ,the cross cutting relations show that the pegmatite is youngest and that aplite is younger than the granite but older than the pegmatite4 ,in the distance is ,kettle ,pond and ,kettle ,mountain4 ,,granite ,,aplite ,,pegmatite ,,glaciation ,although the causes of the ice ages remain a matter for conjecture1 the fact is established that the northern part of ,north ,america was covered by a thick sheet of moving ice several different times beginning about a million years ago4 ,as the effect of the last glaciation erased much of the evidence of previous glaciations1 the present topography can be related to that last one4 ,rather accurate dating by measuring the radioactive decay of ,carbon #ad1 indicates that the ice of the last glaciation retreated from the area about #ab1jjj years ago4 ,because the climates between the four glaciations were as warm1 if not warmer1 than our present-day climate1 geologists have speculated that the world may now be in a warm period and that another ice age is scheduled to occur some time in the distant future4 ,the effect of continental glaciation upon a land mass is twofold4 ,first1 the glaciation acts as an erosive agent which tends to scoop out the areas of softer rock and wear down the areas of more resistant rock4 ,secondly1 when the glacier begins to melt1 it drops large quantities of gravel and boulders which had become incorporated within the glacier4 ,most of this material is picked up by the glacier as it moves over the land2 some falls onto the glacier where it occupies a valley4 ,some of the sand1 gravel and boulder deposits left by the glacier are distinctive in form and composition and others are characterized by their complete lack of distinctive shapes1 and the utterly chaotic nature of the material deposited4 ,the deposits at ,groton ,state ,forest seem to be the latter type4 ,erosion and deposition by the glacier ,the shape of ,spicer1 ,owlshead1 ,little ,deer and ,big ,deer mountains are primarily the result of the erosive action of the glacier as it continually moved southward over the land for a great number of years during the last glaciation4 ,when a continental glacier encounters a hill or mountain of resistant rock1 it tends to scour the rock on the up-ice side of the hill and to 8pluck out0 the rocks on the leeward side4 ,for this reason these mountains have broad gentle slopes on the side from which the glacier came and they drop off sharply on the side from which material was removed by plucking action4 ,the last part of ,figure #c illustrates how these mountains may have been formed4 ,such prominent rock exposures which have been subjected to glacial erosion originally showed deep scratches1 called glacial striae1 cut by cobbles dragged along the bottom of the glacier4 ,unfortunately1 on most prominences in ,groton ,state ,forest exfoliation of the rock has erased these markings2 but it is possible that striae may be found on recently uncovered rock exposures4 ,the depressions in which ,groton and ,osmore ponds are located probably represent areas in which the glacier scooped out material to a greater depth than elsewhere either because of channeling of bottom flow between topographically prominent features1 or because of subtle differences in rock hardness4 ,when the glacier retreated1 that is when it was melting faster than it was advancing1 it dropped material in a helter-skelter manner4 ,end moraines1 which are ridges of gravel formed where the front of the glacier was stationary because of a close balance between rates of movement and melting1 are not evident in ,groton ,state ,forest4 ,as far as can be determined1 the material was deposited irregularly over the entire area1 so that boulders dropped by the glacier are found everywhere4 ,these are particularly noticeable around the lakes where the fine material has been removed and the soil and forest cover does not hide the boulders4 ,almost all of the boulders deposited by the glacier are composed of white granite similar to the rock which underlies the entire area4 ,this indicates that most of the boulders have not been transported very far4 ,however1 occasionally boulders are found which are not characteristic of the area and represent rocks brought in from the north4 ,such boulders which are foreign to the area in which they are found are called erratics4 ,most erratics in this area are dark-colored metamorphosed rocks in which the minerals are oriented to give the rock a layered pattern4 ,these are called either gneisses or schists depending on whether the layering is coarse or fine4 ,deposits of the glacier are exposed in two gravel or sand pits near the ,stillwater ,camp site4 ,these deposits are composed principally of sand but contain scattered boulders of different sizes4 ,a few erratics are found in these deposits--particularly a variety of rock which weathers to a soft1 brown porous mass resembling decayed wood4 ,these sandy deposits probably were plastered onto the ground from the sole of the creeping glacier or were simply let down as the glacier wasted away4 ,because of the irregular manner in which the glacier may deposit its load of sand and gravel1 the topography in such areas is uneven and characterized by poor drainage4 ,at a number of places in ,groton swampy areas occur at higher elevation which might normally be expected to be well-drained4 ,some of these areas have become the sites of beaver dams because they are ideal for damming up the water4 ,,geology ,,of ,,nearby ,,areas ,ricker ,mills ,just south of the park at ,ricker ,mills some of the oldest rocks in the area are exposed in the railroad cut just north of the highway crossing4 ,these rocks belong to a thick sequence of similar rocks which are collectively called the ,waits ,river formation4 ,studies in other areas indicate that these rocks belong to the portion of geologic time called the ,ordovician period which was more than #cej million years ago4 ,the ,waits ,river formation represents a series of sediments which accumulated at the bottom of a shallow sea during ,ordovician time4 ,these sediments included both limy and sandy beds1 and fossils may originally have been preserved in some of the beds4 ,sediments of other types later accumulated over the ,waits ,river formation during a long period of geologic time1 so that eventually the formation became deeply buried4 7,see ,figure #c47 ,the sea retreated and the rocks were subjected to high pressure and temperatures during a period of mountain-building4 ,the rocks which had been sedimentary were folded and converted to metamorphic rocks by partial melting and recrystallization of the components4 ,as a result the rocks became schists or marbles4 ,any fossils which may have been present were destroyed or badly altered in the process4 ,this is unfortunate because valuable geologic information as the age of the rocks can be determined from the type of fossils present4 ,the rocks of the ,waits ,river formation at ,ricker ,mills are dominantly mica schists with layers containing limy material4 ,these are too impure to be considered marble but enough lime is present so that they react strongly with acid1 a test for detecting the presence of lime4 ,the schists principally contain quartz1 biotite1 calcite 7lime7 with lesser amounts of muscovite1 feldspar and impurities4 ,the rocks weather to dark colors2 the gray limy beds are particularly susceptible to weathering and turn dark brown to black on the surface4 ,when more lime is present1 the rock weathers to a deep brown porous rock which resembles decayed wood4 ,some boulders of these altered limestones are found in the glacial deposits in the ,state ,forest4 ,an additional factor which makes the rocks in the railroad cut at ,ricker ,mills look 8messy0 is the iron and manganese staining and the formation of mineral crusts on the surface of the rocks through the action of ground water4 ,rain water falling on the hills above passes through the soils1 dissolving minerals1 and precipitating them where the water seeps out and evaporates at the lower level of the railroad tracks4 ,the schists trend about ,n4#hj,w4 and dip about #cj to the northeast4 ,along the length of the rock exposures it can be seen that this dip is not constant but varies from #aj to #cj4 ,the variation in dip gives the schists a wavy appearance4 ,at two places along the railroad cut1 the schist has been intruded by granite4 ,as is shown in ,figure #f1 which is a sketch of the rocks exposed on the east side of the railroad1 the granite forms vertical dikes4 ,as the schist ends abruptly at the contact of the granite1 this indicates that the granite formed after the schist4 ,the granite is nearly the same as the granite in ,groton ,state ,forest except that the mica is muscovite rather than biotite4 ,for this reason the granite is lighter in color on fresh surfaces4 ,in general the exterior is dark in color due to the staining of iron from weathering of the mineral pyrite1 an iron sulfide1 which occurs in small amounts in the granite4 ,jerry ,lund ,mountain ,on top of ,jerry ,lund ,mountain occur other outcrops of the ,waits ,river formation and granite4 ,their exact relationships cannot be seen easily because of the thick vegetation4 ,the ,waits ,river formation on ,jerry ,lund ,mountain is composed principally of quartz mica schist4 ,,trips ,,to ,,take ,hiking in the ,state ,forest ,the hike from the end of the road to the top of ,owlshead ,mountain takes only ten to fifteen minutes4 ,a splendid view of the surrounding area1 particularly ,groton and ,kettle ponds1 is obtained from here4 ,if possible1 everyone who visits the park should take this short walk4 ,the granite is well-exposed at the summit and dikes of aplite and pegmatite may be seen4 ,the more venturesome park visitor will want to make other trips away from the 8beaten path0 into the wilderness of the ,vermont woods4 ,the principal difficulty arises in that the wilderness is so real a person may well become lost if he strays too far from the trails4 ,some of the trails have become overgrown so that they are difficult to follow and portions of others have been destroyed by the damming up of brooks by the beavers4 ,it is suggested that in planning hikes information be obtained from the park superintendent about the condition of the various trails4 ,illustration3 ,figure #f4 ,diagrammatic sketch showing the relations between the schist of the ,waits ,river formation and the granite on the east side of the railroad cut1 at ,ricker ,mills4 ,,granite ,,waits ,,river ,,formation ,an interesting hike can be made from ,osmore ,pond to ,deer ,mountain but as the trail is poorly marked1 one must maintain a sense of direction4 ,from the ,osmore picnic area walk south near the shore of the pond to its outlet into ,osmore ,brook4 ,at this point turn left to the northeast and follow the trail which parallels a wire marking the edge of the game preserve4 ,about three-fourths of a mile from ,osmore ,brook the trail meets another trail at right angles4 ,to the left the trail follows the game preserve boundary northwestward4 ,the trail to the right leads directly to the top of ,deer ,mountain where a view may be obtained on the south side of the summit4 ,as an alternate route for returning1 follow the trail along the game preserve to the northwest4 ,some distance beyond a shelter-lean-to the trail divides several times with the main trail leading to ,blake ,hill and other trails to the left leading to the ,osmore ,pond road4 ,a hike along the trail on the north side of ,kettle ,pond to the shelter-lean-tos makes a pleasant trip along the water4 ,also1 the trail from ,owlshead ,mountain to ,osmore ,pond is convenient for a short hike through the woods1 if the trail can be found4 ,quarries at ,east ,barre ,the granite quarries at ,east ,barre are in nearly the same type of rock as that which occurs at ,groton ,state ,forest4 ,the quarry operations are interesting and educational and the quarries afford a good opportunity of seeing fresh1 unaltered specimens of granite4 ,guide service is offered at some of the quarries4 ,,footnotes #a;,granite is a type of igneous rock consisting of large interlocking grains of light-colored minerals4 ,rocks are classified as being either igneous1 sedimentary1 or metamorphic4 ,igneous rocks form by the solidification of molten material2 sedimentary rocks form by the accumulation of sediments derived from older rocks2 and metamorphic rocks form by the recrystallization of older rocks under conditions of high temperatures and pressures4 #b;,dip is the inclination of a surface as1 for example1 a joint surface described above4 #c,schist is the name given to rocks in which the minerals have a parallel alignment due to reorganization of the rock constituents during a condition of high temperature and pressure4 ,the platy minerals1 like mica1 form at right angles to the pressure so that the resulting rock may have a 8bedded0 appearance4 ,illustration3 ,looking northwest over ,groton ,pond toward ,owlshead ,mountain ,illustration3 ,looking north over ,groton ,pond toward ,little ,deer ,mountain ,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