X0 IV&IZ' - 35% Library NEW YO BOTANICA 'Tk) York State Museum Bulletin garde: f Published by The University of the State of New York No. 332 ALBANY, N. Y. February 1943 NEW YORK STATE MUSEUM Charles C. Adams, Director GEOLOGY OF THE COXSACKIE QUADRANGLE, NEW YORK By Winifred Goldring D.Sc. State Paleontologist, New York State Museum WITH A CHAPTER ON GLACIAL GEOLOGY By John H. Cook CONTENTS PAGE Preface 7 Introduction 11 Physiography 11 Drainage 20 Vegetation 29 Fauna 32 Settlement 35 Descriptive geology 42 Cambrian system 48 Nassau beds 56 Schodack formation 64 Canadian and Ordovician sys- tems 84 Deepkill shale 90 Normanskill formation 99 Rysedorph conglomerate .... 119 Silurian system 124 Rondout waterlime 130 Manlius limestone 133 PAGE Devonian system 145 Coeymans limestone 151 New Scotland beds 159 Becraft limestone 174 Alsen limestone 184 Port Ewen beds 190 Oriskany sandstone (includ- ing Glenerie limestone) 195 Esopus shale 205 Schoharie grit and limestone. 212 Onondaga limestone 226 Hamilton beds 235 Structural geology 279 Historical geology 306 Glacial geology, By John H. Cook 321 Economic geology and industries. 357 Bibliography 360 Index 371 CL- UJ c n M366r-Je 41-2000 ALBANY THE UNIVERSITY OF THE STATE OF NEW YORK 1943 Digitized by the Internet Archive in 2017 with funding from IMLS LG-70-15-0138-15 https://archive.org/details/newyorkstatemuse3321newy New York State Museum Bulletin Published by The University of the State of New York No. 332 ALBANY, N. Y. February 1943 NEW YORK STATE MUSEUM Charles C. Adams, Director GEOLOGY OF THE COXSACKIE QUADRANGLE, NEW YORK By Winifred Goldring D.Sc. State Paleontologist, New York State Museum WITH A CHAPTER ON GLACIAL GEOLOGY By John H. Cook CONTENTS PAGE Preface 7 Introduction 11 Physiography 11 Drainage 20 Vegetation 29 Fauna 32 Settlement 35 Descriptive geology 42 Cambrian system 48 Nassau beds 56 Schodack formation 64 Canadian and Ordovician sys- tems 84 Deepkill shale 90 Normanskill formation 99 Rysedorph conglomerate .... 119 Silurian system 124 Rondout waterlime 130 Manlius limestone 133 PAGE Devonian system 145 Coeymans limestone 151 New Scotland beds 159 Becraft limestone 174 Alsen limestone 184 Port Ewen beds 190 Oriskany sandstone (includ- ing Glenerie limestone) .... 195 Esopus shale 205 Schoharie grit and limestone. 212 Onondaga limestone 226 Hamilton beds 235 Structural geology 279 Historical geology 306 Glacial geology, By John H. Cook 321 Economic geology and industries. 357 Bibliography 360 Index 371 ALBANY THE UNIVERSITY OF THE STATE OF NEW YORK 1943 THE UNIVERSITY OF THE STATE OF NEW YORK Regents of the University With years when terms expire 1943 Thomas J. Mangan M.A., LL.D., Cho/vic€llov ----- Binghamton 1945 William J. Wallin M.A., LL.D., Vice Chancellor - - - Yonkers 1950 Roland B. Woodward M.A., LL.D. - - Rochester 1951 Wm Leland Thompson B.A., LL.D. - -- -- -- - Troy 1948 John Lord O’Brian B.A., LL.B., LL.D. ------- Buffalo 1952 Grant C. Madill M.D., LL.D. ---------- Ogdensburg 1954 George Hopkins Bond Ph.M., LL.B., LL.D. Syracuse 1946 Owen D. Young B.A., LL.B., D.C.S., L.H.D., LL.D. - - New York 1949 Susan Brandeis B.A., J.D. - -- -- -- -- -- New York 1947 C. C. Mollenhauer LL.D. - -- -- -- -- -- Brooklyn 1944 Gordon Knox Bell B.A., LL.B., LL.D. New York 1953 W. Kingsland Macy B.A. - - - Islip President of the University and Commissioner of Education George D. Stoddard, Ph.D., LL.D., Litt.D. Deputy and Associate Commissioner (Finance, Administration, Vocational Education) Lewis A. Wilson D.Sc., LL.D. Associate Commissioner (Instructional Supervision, Teacher Education) George M. Wiley M.A., Pd.D., L.H.D., LL.D. Associate Commissioner (Higher and Professional Education) J. Hillis Miller M.A., Ph.D., Litt.D. Counsel Charles A. Brind jr B.A., LL.B., LL.D. Assistant Commissioner for Research J. Cayce Morrison M.A., Ph.D., LL.D. Assistant Commissioner for Teacher Education Hermann Cooper M.A., Ph.D., LL.D. Assistant Commissioner for Personnel and Public Relations Lloyd L. Cheney B.A., Pd.D. Assistant Commissioner for Finance Arthur W. Schmidt M.A., Ph.D. Assistant Commissioner for Instructional Supervision Edwin R. Van Kleeck M.A., Ph.D. Assistant Commissioner for Professional Education Irwin A. Conroe M.A., LL.D., L.H.D. Assistant Commissioner for Vocational Education Oakley Furney B.A., Pd.M. State Librarian Robert W. G. Vail B.A. Director of State Museum Charles C. Adams M.S., Ph.D., D.Sc. State Historian Arthur Pound B.A., L.H.D. Directors of Divisions Adult Education and Library Extension, Frank L. Tolman Ph.B., Pd.D. Elementary Education, William E. Young M.A., Ph.D. Examinations and Testing, Harold G. Thompson M.A., LL.D. Health and Physical Education, Hiram A. Jones M.A., Ph.D., D.Sc. Higher Education, Law, Joseph Lipsky LL.B. Motion Picture, Irwin Esmond Ph.B., LL.B. Research, Warren W. Coxe B.S., Ph.D. School Buildings and Grounds, Gilbert L. Van Auken B.Arch. Secondary Education, Warren W. Knox M.A., Ph.D. LIST OF ILLUSTRATIONS PAGE Figure 1 Block diagram of the Mid-Hudson Valley region. (After Berkey) 9 Figure 2 Flint Mine hill (Minneberg) and the flats to the west........ 13 Figure 3 Notch between High Rocks and Roberts Hill. 17 Figure 4 Leeds gorge, looking south-southwest 18 Figure S Hamilton hills north of Coeymans Hollow, with thick glacial covering 21 Figure 6 West Athens flats 22 Figure 7 Hudson valley north of Stuyvesant, looking southwest toward the Catskills 25 Figure 8 Old Aquetuck fort on Shear farm, Aquetuck flats. 43 Figure 9 Old four-arch bridge at Leeds 44 Figure 10 Nassau beds, Nutten hook 59 Figure 11 Nassau beds, Judson Point crossing. 60 Figure 12 Oldhamia occidens, a worm trail characteristic of the Nassau beds 63 Figure 13 Diagrammatic section showing relation of the Schodack beds and Normanskill shale near Schodack Landing. (After Dale) 63 Figure 14 Schodack beds above the thrust zone near Schodack Landing. . 73 Figure 15 Schodack brecciated limestone, two miles south of Schodack Landing 74 Figure 16 Schodack shale and limestone, Nutten hook.. 77 Figure 17 Brecciated limestone beds in Schodack formation, Nutten hook. 79 Figure 18 Schodack limestone fossils 82 Figure 19 Deepkill shale in railroad cut at Stuyvesant 95 Figure 20 Deepkill shale graptolites 97 Figure 21 Chert beds in Normanskill formation along Castleton cutoff, south of Schodack Landing 109 Figure 22 N emagraptus gracilis, a diagnostic lower Normanskill graptolite 111 Figure 23 Pitching syncline in Normanskill grit at Matthew point south of New Baltimore 115 Figure 24 Normanskill shale graptolites 118 Figure 25 Quarry in Manlius and Coeymans, Climax...... 137 Figure 26 Manlius waterlime and Coeymans limestone fossils. 141 Figure 27 Coeymans-Manlius cliff north-northeast of Ravena 155 Figure 28 Coeymans limestone at Deans Mills 156 Figure 29 Kalkberg limestone at Deans Mills.. Potholes 167 Figure 30 New Scotland beds fossils 170 Figure 31 New Scotland beds fossils 171 [3] 4 ILLUSTRATIONS PAGE Figure 32 Becraft limestone with chert pebbles, vicinity of Roberts Hill.. 179 Figure 33 Becraft, Alsen and Port Ewen limestone fossils 183 Figure 34 Alsen and Becraft limestones at Black lake 187 Figure 35 Synphoria stemmata, a trilobite from the Glenerie limestone... 203 Figure 36 Oriskany 'sandstone and Glenerie limestone fossils 204 Figure 37 Taonurus cauda-galli, a worm burrow of the Esopus grit 207 Figure 38 Road cut in Esopus shale, vicinity of New York State Voca- tional School reservoir 209 Figure 39 Synphoria anchiops, a trilobite occurring in the Schoharie and Onondaga limestones 215 Figure 40 Sharon Springs formation, Aquetuck 219 Figure 41 Joint block of Onondaga limestone with numerous chert bands, vicinity of Climax 233 Figure 42 Glaciated ledge of Onondaga limestone, vicinity of Greens lake 234 Figure 43 Schoharie and Onondaga limestone fossils • 236 Figure 44 Bakoven shale fossils 246 Figure 45 Falls over Stony Hollow member of the Marcellus formation.. 257 Figure 46 Typical Hamilton hills, Alcove reservoir 258 Figure 47 Mount Marion beds brachiopods 264 Figure 48 Mount Marion beds fossils 265 Figure 49 Ashokan shale and sandstone, Potic reservoir spillway 271 Figure 50 Panoramic view taken near Leeds and looking across the Catskill valley and Hamilton hills to the Catskills 275 Figure 51 Stereogramic map and sections of the southwestern part of Albany county. (After Darton) 289 Figure 52 Overthrust of Lower Cambrian Schodack formation upon the Ordovician Normanskill shale, south of Schodack Landing... 293 Figure 53 South end of the “Canoe”, a faulted synclinal valley south of Black Lake 294 Figure 54 Anticlinal fold in Esopus shale, Leeds gorge. Glenerie and Port Ewen limestones in stream bed 299 Figure 55 Near view of Esopus anticline in Leeds gorge 300 Figure 56 Doming of Schoharie and Onondaga limestones in Leeds gorge. 301 Figure 57 Diagram showing positions of snow ceiling 322 Figure 58 Diagrammatic cross section of a valley of the form of the Hudson valley and stages in the downwastage and dissection of a stagnant glacial ice tongue 326 Figure 59 Diagram showing typical forms of deposit made in association with masses of stagnant ice 327 Figure 60 Diagrams showing theoretic development of fusion basins in thin stagnant ice 330 Figure 61 Sketch map of the Coxsackie quadrangle showing distribution of the more important glacial features 331 ILLUSTRATIONS 5 PAGE Figure 62 Typical isolated “kame,” two miles northwest of Urlton 333 Figure 63 “Kame” with boulders, about one-quarter of a mile north of Surprise 334 Figure 64 Cluster of “kames,” about one and three-quarters miles north of Urlton 337 Figure 65 Catskill creek north of Cairo 338 Figure 66 Surficial gravels exposed in borrow pit on the top of the terrace shown in figure 65; just west of the Jan de Bakker’s Kill confluence 339 Figure 67 New Baltimore glacial delta, looking west 343 Figure 68 Ice contact face of New Baltimore glacial delta 344 Figure 69 Sloping clay surface north of West Coxsackie 349 Figure 70 Typical high level glaciated bedrock showing striae. Near Newrys 355 Figure 71 Wooded drumlins as seen from Sanford’s Corners, looking southwest 356 Map 1 Geologic map of the Coxsackie Quadrangle In pocket at end Map 2 Geology of the eastern portion of the Coxsackie quadrangle and western portion of the Kinderhook quadrangle In pocket at end Map 3 Geology of the limestone belt from the vicinity of Climax south, enlarged three times In pocket at end GEOLOGY OF THE COXSACKIE QUADRANGLE, NEW YORK1 By Winifred Goldring D.Sc. State Paleontologist, New York State Museum WITH A CHAPTER ON GLACIAL GEOLOGY By John H. Cook PREFACE The area covered by the Coxsackie quadrangle (latitude 42° 15' to 4 2°3(y; longitude 73°45' to 74°) lies in the Hudson valley be- tween the Albany quadrangle on the north and the Catskill quad- rangle on the south and includes parts of Albany, Greene (in large part), Rensselaer and Columbia counties. The work was under- taken in order to continue the mapping of the Devonian formations, particularly, and to fill in the gap between the already mapped Capital District area and the Catskill quadrangle mapped by Doctor Ruedemann and Dr G. H. Chadwick. The work was started in June 1934 and practically completed in the fall of 1937. In order to draw the boundary lines correctly along the eastern border of the quadrangle, it was found necessary to study the same formations on the western border of the Kinderhook quadrangle, where the majority of the outcrops were located. The results are embodied in a black and white map accompanying the geological map of the Coxsackie quadrangle. An overprint to indicate masking glacial deposits has only been used where large areas are covered, as in the broad belt between Urlton and Newrys and the Cambrian- Ordovician belt bordering the Hudson. A third map, printed in black and white, shows enlarged (three times) the complicated geology of the limestone belt from the vicinity of Climax southward. It is suggested that the formations on this map be colored, prefer- ably with colored pencils. The writer wishes here to express thanks to Dr Charles C. Adams, Director of the State Museum, for his unfailing interest in the work as it progressed and to her colleagues on the Museum staff : Dr Rudolf Ruedemann, former State Paleontologist, Dr D. H. New- land, former State Geologist, and C. A. Hartnagel, State Geologist, for assistance of various kinds. Doctor Ruedemann accompanied the writer on a large number of the trips in the area underlain by 1 Including a short discussion of the new Stony Hollow member (p. 247) of the Hamilton beds and a note on the restricted Berne member (p. 249) by Dr G. Arthur Cooper, U. S. National Museum, Washington, D. C. m 8 NEW YORK STATE MUSEUM the Cambrian and Ordovician beds and visited with her, toward the close of the work, some critical localities in the limestone belt south of Greens lake. To him especial acknowledgment is here made. Thanks are also due T. Y. Wilson who on a few occasions ac- companied the writer and Dr Ruedemann on field trips. The writer has had assistance, helpful suggestions and information in the field from Dr G. H. Chadwick and Dr G. A. Cooper of the U. S. National Museum. Doctor Cooper also kindly consented to write a chapter on his new Stony Hollow member of the Hamilton beds. The glacial chapter was written by John H. Cook who has for years studied the glacial geology of eastern New York and already produced similar chapters for the bulletins on the Berne quadrangle, Capital District and Catskill quadrangle. To Walter J. Schoon- maker, Assistant State Zoologist in the New York State Museum, the writer is indebted for faunal lists. To Professor Charles P. Berkey acknowledgment is made for permission to use a portion of the block diagram of the Mid-Hudson Valley region. The writer wishes to acknowledge here also the many courtesies received, while in the field, from the residents, permanent and sum- mer, of the area covered by this quadrangle. Interest, understanding and kindness were met with on all sides. In particular, acknowledg- ment is made to the Rev. Delber W. Clark, former rector of Christ Episcopal Church in Coxsackie, local historian and amateur geologist, from whom many facts of interest, historical and otherwise, were gleaned. Because of the local interest expressed in this work and because of the large number of summer residents, especially in the southern part of the area, an effort has been made to make the in- formation in this bulletin useful to the layman as well as to the scientist. For the various formations discussed are given the rela- tions with neighboring areas and in the State as a whole. A short discussion of each period has been thought advisable as an introduc- tion to the discussion of the formations of that period and the his- torical chapter is therefore less detailed. The photographs used in this bulletin were made by the late staff photographer and draftsman, Edwin J. Stein, to whose skill is due a number of the pen and ink sketches of fossils. After his death this work was completed by the technical assistant in paleontology, Clinton F. Kilfoyle. Except for the Cambrian (Schodack) fossils; which were taken from C. D. Walcott: Cambrian Faunas of North America (U. S. Geol. Surv. Bui. 30, 1886), all the drawings of fossils were taken from various museum publications. Hsrure 1 Block diagram of the Mid-Hudson Valley legion. Ils, Tmvood limestone (Precambrian) ■ Wh Wanninmr limestone Del. Latskill beds (Upper Devonian). Scale, five miles to seven-sixteenths of an inch. (After Berkey) GEOLOGY OF THE COXSACKIE QUADRANGLE 11 INTRODUCTION PHYSIOGRAPHY The Coxsackie area may be roughly divided into three belts : the Hudson Valley lowland developed upon the Cambrian and Ordo- vician beds, into which the present Hudson River trench has been cut; the folded and faulted limestone belt known here and in the region to the south as the Kalkberg (lime hill), and west of this the broad belt of the Hamilton sandstones and shales, occupying about half of the area covered by the quadrangle (figure 1). All of these belts are, however, a part of the Hudson valley which stretches in width from the eroded Catskill escarpment on the west to the Taconic Mountains area on the east which is distinguished from the Hudson valley chiefly by the fact that the Cambrian and Ordovician formations composing it are highly metamorphosed and therefore resistant. The coarser features of the topography have resulted from the general erosion of the country, controlled by the rock structure; details have been added during the advance or re- treat of the ice in the Glacial Period and by postglacial erosion. The differences of level are considered to “arise from (1) the presence of more than one peneplain, (2) the imperfections of peneplains, especially where the rocks have been strengthened by metamorphism, (3) glaciation, (4) crustal movements associated with the Pleisto- cene ice” (Fenneman, ’38, p. 209). Ruedemann in his bulletin on the Capital District (’30, p. 19-21) distinguished three peneplain levels: the broad inner lowland designated as the Albany (Somer- ville) peneplain and regarded as an incipient peneplain of late Tertiary age; the Helderberg peneplain of early Tertiary (Eocene) age, correlated with the Harrisburg peneplain, which rises to a height of about 2000 feet southwest of Albany but descends gradu- ally southward around the Catskills due to the southwest dip of the beds; the Catskill peneplain of Cretaceous age, at or near the top of the Catskills, known as the Schooley or Kittatinny peneplain, which rises to a height of about 4000 feet. It has been suggested that these peneplains may be much younger than supposed (Ashley, ’35). The lowland, or incipient peneplain, embracing the river is gener- ally five to eight miles wide south of Albany. It is now quite flat as much of it is covered by clay or sand laid down during the last stages of the Ice Age in a lake (known as “Lake Albany”) or series of lakes and in delta deposits. On the Coxsackie quadrangle these flats lie between elevations of 100 feet to 200± feet and are 12 NEW YORK STATE MUSEUM in process of dissection by the small streams joining the Hudson which is practically at sea level. In most places the descent to the entrenched river is by steep bluffs of clay (usually) or rocks, 100 feet or more high. On the west side a few low hills or ridges of rock peek through the clay and sand flats, on the east side they are more numerous ; but it might more accurately be stated that these flats were built around and between rock hills or ridges which they had failed to cover, a feature strikingly displayed south of West Coxsackie. An occasional glacial hill also rises above the general level of the flats, such as Lampmans hill, south of Coxsackie, and the Klinkenberg (Echo mountain) two miles south of this (located by School No. 10). The lowland on the west side of the river was developed almost entirely upon the intensely folded Normanskill beds, striking generally N. 20° E., and the resistant grit and chert interbedded with the shale have given rise to the ridges. One such ridge forms the cliff at the lighthouse at Fourmile point, known as Echo cliff. An interesting example is Flint Mine hill (Minne- berg, or Mine hill, of the old settlers), located about a mile and a half south of West Coxsackie road junction. To the east lies a ridge formed entirely by grit (Spoorenberg) ; to the west, another grit ridge (Berg Stuyffsink) with a fertile flat between (figure 2). Flint Mine hill, composed of grit and white-weathering chert ( see page 117), has become well known as the site of the great Algonkin flint mines described by Clarke (’22, from information given by Parker) and Parker (’24). This quarry site was known as early as 1900, but thorough investigation was not made until the years 1921-24. Two hundred flint pits and three large quarries, one of them 150 feet long and 40 feet wide were discovered. The question has been raised whether the quarries were made by the Indians or the early Dutch settlers and it has been stated that traces of old cart roads leading to the quarries have remained into recent times. In places on the hill were found sites of sorting stations, clipping stations, workshops and refuse dumps, some of which were 10 or more feet thick and several hundred feet long. Hundreds of stone maul heads and hammers were found in the pits and the dumps were full of them. Numerous clippings and partly finished blades were found in the various stations, but the largest workshops where the blades were finished were on the flats below the hill. From this locality were obtained for the State Museum by Arthur C. Parker, then State Archeologist, 3000 flint implements, 500 hammers, 50 disks, 3 gorgets, unique in form, a fine mortar and a copper chisel (Clarke, ref. cit., p. 47). Parker, after examination of the hill, be- 13 Figure 2 Flint Mine hill (Minneberg) and the valley to the west of it. looking south and southeast from the grit ridge to the west (Berg Stuyffsink). Such flats (Photograph by E. J. Stein) grit and chert ridges are characteristic of the Normanskill belt. GEOLOGY OF THE COXSACKIE QUADRANGLE 15 lieved (ref. cit., p. 124) that 50 to 100 Indians worked here for at least 1000 years and states that others considered that intermittent work had been going on for over 5000 years. He also points out (p. 123) that, with the possibility of the “demon” of failure lurking in every cranny to cause fracture of the material worked upon, strange amulets were made, usually depicting a serpent devouring some animal, and suggests that the name Coxsackie may thus have originated from the Indian words ahgooks (or skooks) and aki, meaning serpent place. The occurrence of the clay and sand-covered rock terrace along the river indicates post-Harrisburg uplift and the inner gorge or trench a further uplift, just as uplift of the Schooley peneplain preceded the development of the Harrisburg peneplain suggested in the more or less concordant tops of the Hamilton hills. Above this early Tertiary peneplaned surface Cairo Round Top rose as a hill of more resistant rock, a monadrock. The limestone belt, the Kalkberg, shows very interesting topo- graphic features, due to folding, faulting (or a combination) and dissection, some of which are mentioned below. The general north- northeast strike of the belt follows the strike of the folding. The escarpment at the east is a striking topographic feature, especially during the fall and winter after the leaves have fallen. It forms a wall, broken only south of Ravena and north of Climax, which rises quite abruptly from the clay plains to heights between 100 and 300 feet, with occasional summits rising above. The cliff is mainly com- posed of the Manlius and Coeymans limestones ; but, as seen on the geologic map, lower and higher formations are more or less involved. On the topographic sheet long straight lines are seen, instead of curves, and contours crowded closely together in this belt. This is due to the fact that the underlying rocks, mainly shale and limestone have been so folded by great pressure from the east that they are crumpled and crowded together in north-south lines. The rocks are also highly jointed across the folds and blocks broken from the parent ledge tend to split off along roughly north-south and east-west lines. This is well shown both on the topographic map and in the topography itself, particularly in certain places along the escarpment, as in High Rocks and west of Flint Mine hill. Interesting features of the limestone belt are the small but conspicuous swells or anticlinal hills seen on the Onondaga flats (Aquetuck flats) west of Aquetuck and north and south. Anticlinal hills and synclinal valleys are common topographic features of the area, sometimes seen in an unbroken series as in the Esopus- 16 NEW YORK STATE MUSEUM Schoharie belt north of the Aquetuck-Coeymans Hollow State road. A north-south anticlinal valley or glade (figure 3) has been de- veloped between Roberts Hill and High Rocks by dissection along the axis of a pitching anticline. The conspicuous hill north of Climax is a domed anticline the eastern half of which has been removed by erosion. One-half mile south of the Climax hotel, along the cliff, the hill capped by Coeymans limestone owes its height to faulting along the cliff. South of the Coxsackie-Bronks Lake road, in the vicinity of the State reservoir, a narrow valley or glade, extending southwestward, has developed along a faulted anticline on the east. Greens lake is located in a roughly east-west synclinal basin devel- oped across the north end of a pitching anticline and complicated by faulting. Black lake lies in a north-south synclinal basin faulted at the east (figure 34). The north-south canoe-shaped valley (the “Canoe”), located west-southwest of Black lake is a sharp syncline, faulted or broken at the east (figure 53). In the spring, after the snows have melted, and during a rainy season the bottom of the “Canoe” is covered with water for more than half its length and has the appearance, looking north from the southern end, of a small river with steep banks. The high ridge extending beween Leeds and Limestreet is a broad anticline, with steep western arm, modified by dissection. The ridge immediately south of the west end of Greens lake is the axis of the dissected anticline, the higher beds forming ridges on the east and west along the two north-south roads. In the domed southern end of this anticline (figure 4) the Catskill has developed the beautiful Leeds gorge. ( See pages 212, 221-22, 232, 303 and figures 54-56). In the southern third of the quadrangle a rather noticeable, nar- row, flat valley has been developed on the soft black shales (Bak- oven), between the Onondaga belt and the Potic mountain. This valley continues northeastward, but north of Hollister lake is obscured by glacial deposits, and in the northern third or more of the quadrangle these soft shales constitute the lower portion of the Hamilton escarpment above the Onondaga flats. Potic mountain is probably the most conspicuous feature in the belt of Hamilton sand- stones and shales. It is the northward extension of the range of Mt Marion, Mt Airy, Timmerman hill and Vedder hill on the Catskill quadrangle, known as the Hooge Berg (high hill). This range is less conspicuous north of the Climax-Urlton road and about a mile and a quarter north of the Roberts Hill-Medway road ends in a 200- foot clifif. Features of the Hamilton belt conspicuously shown on the map and in the topography, particularly in the northern area [17J Figure 3 Notch between High Rocks and Roberts Hill due to dissection of an anticline pitching north. View looking north from a point on the state road two miles north of West Coxsackie junction. "(Photograph by E. J. Stein) Figure 4 The Leeds gorge, looking south-southwest. The south wall is formed by an anticlinal fold in the Esopus shale (see figures 54, 55) ; the Schoharie and Onondaga limestones form the falls. (Photograph by E. J. Stein) GEOLOGY OF THE COXSACKIE QUADRANGLE 19 and in the southwest corner of the quadrangle, are the steps or ter- races developed upon the harder beds. They are shown on the topo- graphic map by contour lines closely grouped. These terraces, with dip slopes, are most strikingly exhibited on the east and northeast sides of Cairo Round Top. A factor that has largely influenced the shaping of the surface is the great glacier that moved over this area from north to south. In a broad belt extending from Urlton (spelled Earlton by the vil- lage) north-northwest to Newrys may be seen numerous small hills or mounds crowded together and constituting a conspicuous and characteristic feature in the topography (figure 64). Some of these hills contain huge boulders. The ice acted as a great rasp, scouring the rock over which it passed, and the material it picked up was dropped by the overloaded ice, probably in its “melt” stages. Between the mounds are depressions which have given rise to ponds or, as they became partly filled, to swamps. There are very few rock outcrops in this area. The ice plucked the cliffs to the north and east and exposed many north-south rock ledges. In the limestone belt, where the rock is broken up by numerous joint cracks the ice has plucked and carried away huge blocks. This feature is well shown along the east side of the road running north from Limestreet and along the Climax-Roberts Hill road north of the junction with the Medway road. Both areas are underlain by the Onondaga limestone. The large elliptical hills, seen in numbers in the vicinity of Gay- head and northward to the Surprise-Sanfords Corners road, are also a conspicuous element of the topography. These are drumlins or drumlinoids (with rock core) deposited during the late stages of glaciation and are composed of unstratified materials picked up by the glacier ( see figure 71). The longer axis of these hills roughly indicates the direction of advance of the ice. A number of drumlins may also be seen between the Urlton-Climax road and Medway, and there are scattered ones elsewhere. The hills on the north side of the Catskill are heavily banked with glacial deposits which have given them a smooth rounded appear- ance. Outcrops are only found along the roads and in the stream beds. This is in contrast to Cairo Round Top and the terraces to the north and east of it which have been plucked of their covering exposing rock ledges. In general a mantle of drift covers the whole area, sometimes a thin veneer, again heavy as in the above- mentioned area, in the area north of the Hannacrois creek between Alcove and Coeymans Hollow (figure 5) and in the northwest corner of the quadrangle. 20 NEW YORK STATE MUSEUM The clays and sands which have leveled off the dissected surface of the inner valley or lowland of the Hudson river have been men- tioned above. They have to a certain extent been reworked by the small streams so that the flats, particularly noticeable north and south of Coxsackie and north and south of West Athens (figure 6), are underlain by a mixture of alluvium and the glacial sands and clays. The clays forming the flats show a distinct varved structure, an alternation of lighter and darker layers indicative of seasonal deposition in quiet, fresh water. It was formerly supposed ( see Woodworth, ’05) that a single large body of water, known as Lake Albany, occupied the Hudson valley between Kingston on the south and Saratoga and Schenectady on the north ; but the more recent work of Cook (’30) indicates instead a series of smaller lakes held at slightly different levels in the river valley by residual tongues of ice (“dead” ice). Wells in the vicinity of Coxsackie have been driven 80, 135 and 175 feet through the clays before reaching rock (information from the Rev. Delber W. Clark). The clay and sand of these flats also control the character of the stream valleys which show a striking dendritic character on both sides of the river and divide the area into numerous more or less flat-topped hills. Small deltas and terraces formed by streams during the latest stages of the glacial period are in places noticeable features in the landscape. A delta, now being excavated, is well shown at the mouth of the Hannacrois creek on the east side of the State road east of New Baltimore (figures 67, 68). Three terraces, in various stages of dissection, are quite noticeable topographic features in the valley of the Catskill on the north side of the creek : north of Cairo in the vicinity of the bridge across the Catskill, north (Sandy Plain) and east of South Cairo and north-northeast of Leeds at the south end of Potic mountain. For the details of glaciation the reader is referred to the chapter on glacial geology by John H. Cook (page 321). DRAINAGE The drainage in its present form is the result of glaciation. Old stream courses have been filled in and are being reexcavated by the present streams ; or streams have been turned away from their old courses. Small lakes or ponds were formed in the depressions in the midst of glacial deposits and through draining or partial filling many of them have become swamps. The entire area is drained by the Hudson river and its tributaries, large and small. In this part of its course the Hudson carries a large amount of debris, brought in [21] Figure 5 The Hamilton hills north of Coevmans Hollow as seen from the hill above (south of) the cemetery. Such hills, heavily covered with glacial deposits, are characteristic of this area. (Photograph by E. J. Stein) Figure 6 West Athens flat, looking north-northeast from the Kings roach (Photograph by E. J. Stein) GEOLOGY OF THE COXSACKIE QUADRANGLE 23 by its tributaries, and as the river is here at tide level much of the material is dropped in the channel in the form of islands, producing a “braided” stream. The rocky Barren island has in recent years been connected by a sand flat with the mainland at Coeymans in the course of dredging operations. The name should be. Rarent’s or Baerent’s island, after Barent Pieterse Coeymans who received a patent starting from this island, as the county line now does. Across the river from Coxsackie two other rocky islands are connected with the mainland by alluvium, Nutten hook and Little Nutten hook (properly Noetten hoek : “nutty” corner). The Hudson river existed long before the Glacial Period, at least as far back as Cretaceous time, over 75,000,000 years ago. At the dose of the Paleozoic this section of the continent was elevated and after eons of time was worn down to a low plain, the Cre- taceous peneplain over which the streams wandered regardless of structure. Subsequent elevation, which continued into Tertiary time rejuvenated the streams which again reduced the area from the Catskill mountains on the west to the Taconic mountains on the east to a low-lying plain (see pages 318-20), the present broad valley of the Hudson and its tributaries. The enormous amount of work involved can be grasped if one remembers that the river and its tributaries have not only removed the rock between the tops and bases of these ranges but also the continuation of these formations that once extended farther north and lapped upon the Adirondacks. Even at the end of Tertiary time the country stood much higher than now. The Hudson had a course, now buried under the ocean, nearly 100 miles beyond the site of New York. The gorge which the river had cut for itself extended from Albany to its mouth. Near Albany the rock surface is now more than 100 feet below sea level. At the Highlands the canyon is more than 700 feet deep, while beyond New York it goes down, according to Veatch and Smith (’39, plate 1) about 8000 feet at a place about 50 miles beyond Sandy Hook, the buried Grand Canyon of the Hudson. All these facts indicate not only a much greater elevation but an extension of the coastal section of the continent eastward. (See Ruedemann, ’32, ’39, 42 b: Catskill bulletin ; Johnson, ’31 ; Meyerhoff and Olmsted, ’36, for history of the Hudson river.) The Hudson river held its preglacial course through the various glacial and interglacial periods and is now entrenching itself within the clay flats which are in process of dissection by the small streams tributary to it (figure 7). Since the new gorge in the clay is narrower than the rock gorge the bluffs of the river in many places consist 24 NEW YORK STATE MUSEUM of clay. Where both the Hudson and the tributaries are working in the soft clays they meet at grade, but in a few places the tribu- taries have encountered rocks and descend to the level of the river by falls, thus forming “hanging valleys.” Examples are seen in Coeymans creek at the north outskirts of the village, in the stream just south of the Rensselaer County line on the east side of the river and in the stream south of Poolsburg just east of the Castle- ton cutoff. On the east side of the river the tributaries are of small sizes and, because their courses are in large part in the deep clays, have developed the characteristic dendritic type of drainage. Mill creek, three-quarters of a mile due east of its mouth, has encountered the rock of the old valley floor. Stockport creek which with its two tributaries, Claverack and Kinderhook creeks, drains much of the northern and western area of the Kinderhook quadrangle, empties into the river three and one-half miles north of the city of Hudson. At Columbiaville, where the highway bridge crosses, the creek has been forced to cut down through Cambrian shales and sandstones, producing a gorge where once there must have been a falls, since base level and would have been reached comparatively quickly by the stream in that portion of the valley, underlain by clays, between this point and the river. The west side of the Hudson river on the Coxsackie quadrangle is drained largely by the Hannacrois, Coeymans, Coxsackie and Mur- derers creeks, and the Catskill, with their tributaries. Coeymans creek at the north and Murderers creek (Modder or Mordaener kill= Muddy creek) north of Athens are confined to the clay flats in the Ordovician and have the same character as the streams on the east side of the river. The courses of the other three creeks, with their tributaries, are confined largely to the area underlain by the Devonian rocks, the limestone belt and the belt of the Hamilton shales and sandstones. The Hannacrois (correctly Haane- kraaie or “Cock Crow” creek, from Dutch haan, cock ; kraai, to crow) is characterized in the vicinity of Coeymans Hollow, and east and west, by tributaries with steepsided valleys extending north- northeast and south-southwest. From the topographic map one has the impression of valleys gouged out by the ice ; but no evidence for this was found in the field and the indications are these valleys are controlled by one set of the master joints found in the Hamilton beds. The Hannacrois has developed two broadly open valley sec- tions in its upper course, one controlled by the falls developed on resistant beds at Dickinsons falls (Dormansville) ; the other by a similar falls at Alcove, an area now the site of the Alcove reservoir, H cn ,-C r * £ U o