PALEOZOIC TIME — CAMBRIAN. 467 



Eastern Border Begion. — In southeastern Newfoundland, on Manuel's Brook, occur 

 shales, with some limestone, overlying a conglomerate, in all 400' ; above occur beds with 

 the Paradoxides fauna, and below it, within 40' of the conglomerate, species of the 

 Olenellus faiuia ; the former occurs also at Topsail Head and on Conception Bay 

 (Walcott). In the Acadian trough. Lower Cambrian fossils are reported from the north 

 side of the Straits of Belle Isle, at L'Anso au Loup, and on the opposite coast at Canada 

 Bay, Labrador ; Middle Cambrian, as gray and black shales, in New Brunswick, near 

 St. John, with also Upper Cambrian beds ; in eastern Massachusetts ; the Lower Cambrian 

 at Nahant, and in Bristol County, near northeastern Ehode Island, and the Middle Cam- 

 brian at Braintree, where a thick conglomerate, much flexed, underlies 500' to 1000' of 

 slate. 



Continental Interior Begion {west of the Appalachian protaxis). — Along the Green 

 Mountain region in Vermont and Massachusetts, among the rocks of the Taconic series, a 

 great quartzyte formation, having intercalations of hydromica and mica schist and occa- 

 sionally ottrelite schist, has been shown by fossils to be in part or wholly Lower Cam- 

 brian, The Sillery sandstone of Logan, in Canada, is part of the quartzyte formation. 

 The limestone (white marble), adjoining the quartzyte on the west, has afforded Lower 

 Cambrian fossils to the eastward and northward of Kutland. The continuation of this 

 limestone belt, in Massachusetts, called the Stockbridge limestone, is too highly crystalline 

 for fossils ; it may be in part Cambrian. West of the Taconic limestones in central Ver- 

 mont, Lower Cambrian is represented by the red sandrock of the region. In north- 

 eastern Vermont, at Georgia, magnesian limestone, 1000' thick, is overlaid by a great 

 thickness of shales ; at Highgate the same limestone is 1200' thick. * 



The reddish, mottled "Winooski limestone," of the Georgia Cambrian, is worked for 

 marble at Swanton. 



West of the New England line. Lower Cambrian occurs in Washington County, New 

 York, near Bald Mountain and elsewhere ; in the western part of Rensselaer County, at 

 Troy, in shales and limestone and at Schodack Landing ; at several places in Dutchess 

 County, at Stissing Mountain, where Middle Cambrian fossils also occur. 



West of Lake Champlain, about the Adirondacks, the Potsdam sandstone, chiefly 

 Upper Cambrian, has a thickness in St. Lawrence County of 60' to 70' ; in St. Lawrence 

 valley, of 300' to 600' or more ; in Warren and Essex counties, of about 100'. But in 

 Dresden, Washington County, it occupies a depression at a height of 912' above Lake 

 Champlain. A lower portion of the sandstone, according to Walcott, is Middle Cam- 

 brian. 



In New Jersey, Sussex County, at Hardistonville, Olenellus occurs in sandstone, and 

 other Cambrian fossils in the Magnesian limestone near Franklin Furnace, and north of 

 Franklin Furnace Pond (C. E. Beecher) . Foerste has found the Olenellus fauna in the 

 same region, and also south of Sparta Junction, northeast of Long Pond ; and he has 

 traced it southwestward into eastern Pennsylvania ; he shows that the quartzyte of the 

 region, instead of being Potsdam Upper Cambrian, is mostly Lower Cambrian as in Ver- 

 mont (1893). 



The Lower Cambrian has been traced by Walcott from New Jersey southwestward 

 across Pennsylvania. In southeastern Pennsylvania, west of the Susquehanna, over 

 parts of York, Adams, Franklin, and Cumberland counties, about South Mountain, east 

 of the river in Lancaster County, and in adjoining parts of Maryland, the Lower Cam- 

 brian includes a great thickness of quartzyte with overlying shales or slates and limestone ; 

 and besides these rocks there are, in South Mountain, large flows of basaltic and rhyolytic 

 rocks. In Virginia, fossiliferous shales of the Lower and Middle Cambrian occur near 

 Natural Bridge and Balcony Falls. 



W. B. Rogers states, in connection with a contribution on the geology of Virginia to 

 Macfarlane's Geological Baihoay Guide (1879), that the "Potsdam or Primal Group, 

 where complete in Virginia, includes, besides the Potsdam sandstone proper, the ferrife- 



