These are underlaid by the Potsdam group, 2020 feet in thickness consisting of quartzites, dolomites and shales. 15. Bird's Eye, Black River and Trenton formations, 639 to 648. Localities represented. Paquette Rapids, Pointe Séche, Montreal, Pointe aux Trembles. Fossils 48-52. Sir W. E. Logan says, (Geology of Canada, 1863,) "The Bird's Eye, Black River and Trenton formations constitute one of the most persistent and conspicuously marked series of strata of the Lower Silurian period on the continent of North America. They first appear to the north-east in small outliers at Murray Bay and Lake St. John, resting on the Laurentian, and from Cape Tourmente below Quebec they have been traced with an almost unbroken outcrop for a distance of nearly 2000 miles westward, into the southern part of Minnesota, where they are overlaid and concealed by newer rocks." They re-appear in Canada to the north, in the Province of Manitoba, whence they have been observed at intervals, and probably form a continuous belt, to the shores of the Arctic Ocean. They have not been certainly identified in Canada on the east side of the St. Lawrence and Champlain fault, unless some portion of the black slates and plumbaginous limestones included hitherto in the Levis division of the Quebec group are of this age, which the fossils recently found in them would seem to indicate; or else that we have in the Levis formation of the Eastern Townships a commingling of forms similar to that noticed above as occurring in Newfoundland. 16. Utica Slate and Hudson River formations, 649 to 675. Localities represented. Collingwood, Gloucester, Lake St. John, Cote St. Michel, St. Marks, Anticosti With the Hudson River rocks are placed a few specimens of the intrusive rocks, dolerites, diorites and trachytes, which are intruded among the members of the Lower Silurian series, but which may themselves be of much more recent date. "The most remarkable of these in Canada form a line of isolated hills, eight in number, extending about ninety miles along the line of an undulation, which has disturbed the Lower Silurian strata. These hills, beginning from the west, are Rigaud, Mount Royal, Montarville, Beloeil, Rougemont, Yamaska, Brome and Shefford mountains; to which may be added Mount Johnson or Monnoir, a little to the south of this line. These masses have been left by denudation as hills covering areas of several miles and sometimes more than 1000 feet in height, and present great varieties in composition. Brome and Shefford are granitoid trachytes, Yamaska, partly trachy te and partly diorite; to which latter rock also belongs Beloeil, so far as examined, and Monnoir. Rougemont, Montarville, and Mount Royal are dolerites, and Rigaud is, in great part, a granitoid trachyte' Dykes of numerous varieties of trachyte and of phonolite, cut the dolerites of Mount Royal, and the shales of the Hudson River formation. The conglomerate of St. Helen's Island, which overlies and encloses masses of Upper Silurian limestone, as well as fragments of granitoid dolerite, is in its turn traversed by dykes of a newer rock, which is also a dolerite. The strata in the vicinity of these intrusive masses are not altered except near the line of contact." The lithological characters of the Utica and Hudson River formations are not specially interesting: the strata composing them are made up of black graptolitic shales, arenaceous shales, sandstones and limestones. Like the preceding group they have not been found in Canada to the south-east of the great fault. IV. MIDDLE AND UPPER SILURIAN. 17. Medina and Clinton formations, 676 to 678. Localities represented. Grimsby, Dundas, Hamilton, Limehouse. Fossils 78-80. 18. Niagara formation, 683 to 693. Localities represented. Dundas, Grimsby, Rockwood, Thorold, Anticosti. Fossils 81-89. 19. Guelph formation, 694 to 695. Localities represented. Guelph, Galt. Fossils 90-98. UPPER SILURIAN. 20. Onondaga formation, 696 to 698. Localities represented. Goderich, Oxbow, Cayuga, This is the great salt and gypsum bearing formation of Western Canada. Bolton, Shipton, Chaudière, Temiscouata Lake, Rivière du Loup, Gaspé. 23. New Brunswick. Chamcook Lakes, Petersville, Moore's Mills, Oak Bay. Queens Brook, Nerepis Valley, Woodstock.* 24. Nova Scotia 736 to 753. Arisaig, Frenchman's Barn, East River, Malignant Cove, Doctor's Brook Fossils.-107 Arisaig. Some of the specimens included with the above (736 to 753) are probably older than the group with which they are placed. They may belong to the Laurentian series which is exposed at intervals from Cape St. George to Cape Chiegnecto i but the relations and distribution of which in this region have not yet been studied by the Canadian Geological Corps, but are indicated on the coloured geological map of the Lower Provinces. The valuable deposits of iron ore, hematite and limonite of Londonderry, Pictou, &c., in Nova Scotia, are associated with these Upper Silurian formations. V. DEVONIAN. 25. Oriskany and Corniferous formations, 754 to 750, The distribution of these formations is shown on the large geologically coloured map of Canada, and they have been fully described by Sir W. E. Logan in the fourteenth chapter of the "Geology of Canada." As the source of all the petroleum produced in the Dominion, and as affording excellent lime and fine building stone they are of great economic importance. 27. Devonian of Eastern Area. Formations 25 and 26 of the Western Area 757 to 781, Localities represented. Beloeil, Gaspé, Port Joli, Matapedia. Mispec Creek, St. John, N.B., Nictaux, N.S., and Peace River, B.C. Fossils 134-141. VII. ROCKS OF BRITISH COLUMBIA. 34. Crystalline rocks of undetermined age, 855 to 884. 35. Silurian, Devonian and Carboniferous formations, 885 to 892. 36. Devonian and Carboniferous formations, 893 to 899. Localities represented. Vancouver and Ballina Islands.c 37. Cretaceous formation, 900 to 902. Localities represented. Queen Charlotte Islands. Vancouver Island. NOTE. In addition to the stratigraphical collection of rocks from the Geological Survey, Dr. Honeyman of the Provincial Museum, Halifax, exhibits a collection of Nova Scotia rocks, Professor How of Windsor, Nova Scotia, a collection of minerals, and Mr. H. S. Poole, of Halifax, a collection of ores and associated rocks. |