walcott.] CORRELATION. 395 



The first cardinal point is the Granular liinerock " the only lime- 

 rock which is always destitute of organic remains." The second car- 

 dinal point is the Metalliferous, Mountain or Carboniferous limerock. 

 Under this heading he correlates the limestone at Trenton Falls and 

 most of the limestones of New York. The third cardinal point em- 

 braces the Oolitic series or Calcareous rocks, and the fourth the Ter- 

 tiary marls. These correlations of Eaton were crude, but when re- 

 fined by the geologists of the New York State survey the first three 

 formed the basis for the correlation of the lower and middle Paleozoic 

 rocks of the continent. 



Bigsby. — The earlier work of Dr. J. J. Bigsby was apparently un- 

 known to Eaton. The former used orgauic remains in a very general 

 manner to correlate the strata of England and America, but also de- 

 pended upon the lithologic characters and stratigraphic succession. 

 In an article entitled "A list of minerals and organic remains oc- 

 curring in the Canadas n he remarks upon the extent and relations of 

 the limestones and sandstones of the eastern and western parts of 

 Canada. Of the limestones he says: 



Their relation to the subjacent rocks and uniform similarity in structure and con- 

 tents, mineral as well as orgauic, seem to indicate that the beds of limestone, extend- 

 ing with few or no interruptions from Cape Tourment, below Quebec, to near the 

 Falls of St. Mary, are the effects of a contemporaneous deposition ; and further, 

 that they are the representatives of the Mountain or Carboniferous limestone of Eng- 

 land. 



I make these statements with extreme diffidence, being in some degree aware of 

 the difficulties of the discussion, of the existence of contradictory facts, few but 

 weighty, and of the defective state of our information respecting the vast calcareous 

 formations of North America. 1 



The reference to the secondary limestone of the St. Lawrence and 

 the lake region is as follows : 



The limestone now described abuts on one of the older rocks directly, or with the 

 interposition of another horizontal stratum, and by far the most commonly on 

 gneiss, which I have strong grounds for believing to be of the same age and general 

 characters throughout the whole of the districts under consideration. It is in- 

 cumbent directly on gneiss in the bed of the river St. Anne, near its upper falls, 

 in the seigniory of St. Feriole, Lower Canada; at Montmorenci, not far from "the 

 natural steps," but only seen in time of low water; at and near Point Henry, close 

 to Kingston, Upper Canada; and in many places on the north coast of Lake Huron. 

 In the last-named locality it rests directly, in several instances, on a beautiful snow- 

 white transition quartz, which occupies the main shore in steep hills, 400 and 500 

 feet high, from near the French River to the River Le Serpent (70-80 miles). The 

 immediately subjacent rock at La Cloche and on the isles north of the Manitoulines, 

 in the same lake, is sometimes a highly inclined greenstone. Near Montreal it 

 overlies directly crystalline trap, containing augite, zeolite, mica, feldspar, etc. 



But ordinarily a sandstone, graywacke, or a.couglomerate of quartzose or calcareous 

 materials is interposed ; also in horizontal layers. It is to be remarked (en passant) 

 that much the greater part of the graywacke of Lower Canada does not belong to 

 this deposition, but is conformable to the mica-slate, gneiss, etc., ranging along the 

 north shore of the St. Lawrence, between Quebec and the river Saguenay. * * * 



'A list of mineral and organic remains occurring in the Canadas. Am. Jour. Sci., vol. 8, 1824, pp. 

 76, 77. 



