166 



STRUCTURAL GEOLOGY OF NORTH AMERICA 



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STANDARD 



RICHMOND 



MAYSVILLE 



EDEN 



GLOUCESTER 



COLLINGWOOD 



COBOURG 



SHERMAN FALL 



ROCKLAND 



CHAUMONT 



LOWVILLE 



PAMELIA 



VALCOUR 



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MIOOLEBURY LS. 

 8EL0ENS FM 



CROWN POINT 



DAY POINT 



///////// 



SMITHVILLE 



COTTER- POWELL 



ROUB1DOUX 



GASCONADE 



TREMPEALEAU 



FRANCONIA 



DRESBACH 



MARJUM 



WHEELER 



SWASEY 



DOME 



HOWELL 



SPENCE 



LANGSTON 



ROME 



SHADY 



ERWIN 



HAMPTON 



UNICOI 



WEST-CENTRAL 

 VERMONT 



HORTONVILLE SL 

 GLEN FALLS LS. 



ORWELL LS. 



BURCHAROS 



BRIDPORT OOL .. 



BASCOM FM. 



CUTTING OOL. 



SHELBUR N.MARBIE 

 CLARENDON SPRINGS 



-■? ? ? 



WINOOSKI DOL. 



MONKTON OT2ITE. 



DUNHAM DOL. 



CHESHIRE OTZITE 



-? ? ? — 



"MENDON SERIES" 



"MT HOLLY SERIES" 



NORTHWESTERN 

 VERMONT 



TstanbridgeI 



L si - J 



[mystic congl] 

 ? 



grandge sl. 

 corliss congl. 

 highgate sl. 



ROCKLEOGE CONGL 

 HUNGERFORO SL. 

 SAXE BROOK DOL. 

 SKEELS CORNERS F 

 MILL RIVER CONGL. 

 ST. ALBANA SL. 



RUGG BROOK FM. 

 PARKER SL. 

 DUNHAM OOL. 

 GILMAN OTZITE. 



WEST SUTTON SL 

 WHITE BROOK OOL. 

 PINNACLE GRAYWCK. 

 CALL MILL SL. 

 TIBBIT HILL SCHT. 



EASTERN 

 NEW YORK 



INDIAN LADDER BED 



ISLE LAMOTTE LS 

 AMSTERDAM LS. 



CHAUMONT LS 



LOWVILLE LS. 



VALCOUR LS 

 CROWN PT. LS. 

 OAY POINT LS. 



BEEK.E 

 CASSIN FM I SEEK. 



A 



BEEK. 01 a 02 ?- 

 BEEK.C * 



— ■ TRIBES HILL 



BEEK B WHITEHALL 



LITTLE FALLS 



DOL. 



THERESA FM. 



NEW YORK 

 QUEBEC 



SNAKE HILL SH. ? 



NORMANSKILL SH 



OEEPSKILL SH. 



SCHAGHTICOKE 



SILLERY SL. ? 



? ? 



SCHODACK SH.B LS. 



BOMOSEEN GRIT 



NASSAU BEOS 



Fig. 11.14. Stratigraphic correlations in west-central Vermont and adjoining areas, after Cady, 

 1945. 



Evidence for the existence of the "Taconic klippe" was not found in mapping 

 this quadrangle. Analysis of the development of the klippe hypothesis indicates 

 that it is based principally upon stratigraphic considerations; available struc- 

 tural evidence weighs against this interpretation. While the klippe hypothesis 

 seems to explain well the relations at the north end of the Taconic Range, 

 the problem of adequately defining the boundaries of this 'Tdippe" causes 

 serious doubt about its existence. 



An alternative interpretation of the regional relations is suggested, involving 

 unconformities and facies changes in a single indigenous sequence. Trentonian 

 rocks lie unconformably on rocks as old as Precambrian from Vermont to 

 Pennsylvania and pass indiscriminately in and out of the "Taconic klippe." 

 The Normanskill and Deepkill rocks (mainly shale) are interpreted as passing 

 transitionally into limestone to the west. The Deepkill is believed to rest 

 unconformably on rocks of Early Cambrian to middle Canadian age. Middle 

 Canadian formations in the kinderhook quadrangle are carbonate rocks and 

 appear to rest unconformably upon Lower Cambrian slates; their striking 

 similarity to equivalent rocks in the near-by "autochthonous" series suggests 

 they have not been displaced any great distance. The lower Cambrian is a 

 thick series of argillite, graywacke, and quartzite with some thin carbonate 

 rocks near the top. The thick, lower part of this series is considered a southward 

 continuation of the Mendon Series of Vermont. The upper strata are interpreted 

 as the offshore equivalents of shallow-water quartzites and carbonate rocks 

 deposited marginal to an eastern welt in later Early Cambrian time. 



Lake Champlain and St. Lawrence Lowlands 



The Champlain Valley lies partly in New England. In the largest view 

 it is bounded on the east by the Green Mountains and on the west by the 

 Adirondack Mountains, and at the south it is split by a minor group of 

 mountains, the Taconic Range. A large part of the valley is occupied by 

 Lake Champlain, the surface of which is 100 feet (30 meters) above sea 

 level and the bottom is below sea level. The valley passes northward into 

 Canada and curves northeastward, merging into the St. Lawrence Valley 

 (Keith, in Longwell, 1933). 



The valley is divided by the Taconic Mountains into a western part 

 which is continuous with the Hudson River Valley, and an eastern part 

 which extends along the eastern side of the range nearly to Long Island 

 Sound. This eastern part of the valley is known as the Rutland Valley in 

 Vermont and the Stockbridge Valley in Massachusetts. 



The St. Lawrence lowlands are of two divisions separated by the fault 

 known as Logan's line ( Fig. 12.2 ) . Southeast of the fault is the deformed 



