108 DR ROBERT BELL ON 



exist in Euphemia, both by the dip aud distribution of the rocks. At Smith's Mills, in 

 this township, it interrupts the overlying Portage group, and brings to the surface the 

 limestones of the Hamilton formation, with a north-westward dip of 40 or 45 feet to the 

 mile. (Report of Mr. Alex. Murray for 1850, p. 29). Between this undulation and the main 

 axis in Enniskillen, about 150 feet of the black Marcellus shales have lately been found 

 by borings in a trough between the two auticlinals, in the north-eastern part of Dawn. 

 In the Ontario oil-field, the drillers consider it a bad sign to strike these black shales, as 

 experience has tavight them that, in such cases, no oil is to be found in the underlying 

 Corniferous limestone, the reason apparently being that these shales occupy only the syn- 

 clinals in the oil-bearing formation. 



The transverse undulations appear to follow two principal courses, one about east and 

 west, and the other north-westward. The anticlinal of the head of Lake Ontario, and 

 the sharper one of Rockwood and others further north, are examples of the former. In 

 northern Ohio the formations dip northward at very low angles along the line of the 

 Cincinnati anticlinal, but a transverse vxplift seems to run east and west through the 

 natural gas field of Lima, for Prof Orton says (p. 28) that " the surface of the Trenton lime- 

 stone is approximately at the same level at Yan Wert, Lima, and Upper Sandusky, or 

 along an east and west line 60 to TO miles in length." The great spread of the Corniferous 

 formation in north-eastern Indiana is probably due, in part, to an elevation of the rocks 

 running in this direction from the vicinity of Lima to the south end of Lake Michigan. 

 About latitude 42" the strata strike east and west all the way from the Hudson River to 

 the Mississippi, except where this parallel intersects the Cincinnati anticlinal, and it is 

 somewhat remarkable that west of the Appalachian range the southern boundaries of all 

 the Archeeau areas, just above this latitude, lie in an east and west line across the entire 

 continent. These facts are mentioned as having a possible bearing on the formation of 

 east and west auticlinals in the regions under discussion. The course of the oil-producing 

 belt in Enniskillen and Euphemia is probably evidence of the existence of a north-west- 

 ward undulation in these townships, and the fact that th'e Bothwell oil-field lies south-east 

 of this reo'ion, may be an additional fact pointing in the same direction. An undulation 

 in the Corniferous limestone, rvinuing nearly north-west, is to be seen on the 13th lot of 

 the 1st range of Rainham, on the north side of Lake Erie ("G-eology of Canada," p. 379). 

 In the vicinity of Milwaukee there are distinct evidences of north-westerly folds in the 

 strata. It may be worthy of note in this connection that if a straight line be drawn at 

 rjo-ht ano-les to the centre of the great north-westward curve in the folded strata of the 

 Alleo-hany Mountains in Pennsylvania, it would have a west-north-west course, and would 

 pass in the vicinity of the Enniskillen oil-field. 



From what has been said in regard to the anticlinal theory aud the accumulation of 

 petroleum, it follows that the most probable sites for searching for this fluid in the regions 

 iust described, are at points where the great anticlinal is intersected by one of the trans- 

 verse folds whose existence has been indicated. Owing to the depth of the drift and the 

 infrequency of exposure of the underlying rocks, we must depend principally on the "logs" 

 of wells drilled in various parts of the possible oil region for the data to guide us ; hence 

 the importance of preserving these records, even if the wells have failed to answer the 

 purposes for which they were originally sunk. These records are also of much value in 

 determining the actual thickness of the Silurian and Devonian formations in western 



