MICHIGAN ACADEMY OF SCIENCE. 79 



Were there sufficient exposure of the rock surface to faciUtate observa- 

 tion, the dip of the overlying formation would doubtless be seen to circle 

 round the anticlinal as this falls away eastward, until the north to north- 

 westerly dip would be found again on the north side of the anticline, the 

 same dip as on the opposite side of Detroit river. 



Let it be noted that there is a Silurian surface extension immediately 

 northward of the Amherstburg Quarries. The log of the Sucker Creek 

 Oil and Gas Company's test well, lot 7, con. 6, in Anderdon Township (some 

 six miles northeast from the point A' in the diagram), shows dolomite from 

 the surface down, 350 feet of it over the Sylvania. 



The Rock Surface of Essex County falls away eastward from an elevation 

 ■of 609 feet at the quarries in Anderdon, to 533 feet at Essex town near the 

 center of the county. There is a further fall to 476 feet at Comber, and 

 to something less than this at the Kent county line. (This is a medial line, 

 both territorially and with reference to surface drainage.) From the same 

 starting point of 609 feet elevation, eastward through the southern part of 

 the county, there is the same falling away, but less pronounced. At Marsh- 

 iield, southeast from the highest point of rock elevation in the county, at 

 the Amherstburg Quarries, and southwest from Essex town, the rock eleva- 

 tion is 521 feet. At Leamington, southeast of Essex town and south of 

 Comber, it is 502 feet; and at the county line less than 500 feet. In the 

 northern part of the county the elevation of the rock surface is 492 feet at 

 Belle River; and there is evidence that it is lowest at the northeast corner 

 of the county, at the mouth of the Thames river. 



Were the analyses forthcoming they would, therefore, doubtless show, 

 not only that the Corniferous extends into Essex county along the ascertained 

 lines of outcrop in Monroe and Wayne counties, overlain northward by the 

 Hamilton and Genesee, in order; but also that it circles round as above sug- 

 gested to where it has the southward dip as exposed in the Amherstburg 

 Quarries. 



I make the statement on the authority of Mr. Eugene Coste, late mining 

 engineer of the Geological Survey of Canada, who has done a great deal of 

 exploring for gas and oil in both Essex and Kent counties, ihsit" the western 

 limit of the black shale is, roughly speaking, the Essex and Kent county line; 

 and in places in Kent county these shales extend south as far as Lake Erie; 

 although they are missing in Kent over a number of anticlinal folds." There- 

 by establishing two things: First, and incidentally, that the contour of the 

 AJitrim or Genesee shales, as figured in the 1903 report of the Michigan 

 Geological Survey, errs by defect, as does also the outline mapped by the 

 Dominion Government Survey, in showing the extent of tliese *shales; 

 and second, (and more to the purpose of the argument in hand to establish 

 the fact of a Silurian anticlinal in the western part of Essex county), that 

 anticlinals have interfered to displace later deposits in this southwestern 

 section of Ontario. A Silurian anticlinal is the solution of the problem 

 offered. For that matter the Lime Kiln Crossing in the immediate neigh- 

 borhood of the Amherstburg Quarries, in the Detroit River, known to 

 sailormen as the danger spot of the lakes for deep draft boats, is part of 

 a Silurian anticline. 



* Well records show a varying depth of these shales at the North side of Kent County 

 from Dresden to Bothwell, of 180 feet, 146 feet, 98 feet, 200 feet, and 77 feet. 



