PETEOLEUM IN ONTAEIO. 107 



the deepest and longest part of the immense physical and geological depression of Hudson 

 Bay and Fox Channel. The line would next pass through an elongated Silurian area in 

 the midst of the Archaean, and thence by Smith Strait, Kennedy and Eobeson Channels, or 

 the direct chain of waters followed by explorers to the most northern points which have 

 ever been reached by man. The long chain of volcanic islands in the eastern part of 

 Hudson Bay lies directly along this line, and the existence of immense north and south 

 dykes of trap for a great distance south of James Bay, was pointed out in my report for 

 1875? Great north and south masses of trap occur on this line around Lake Temagami ; 

 and at the mouth of French Eiver which is also on its course, I am informed by Com- 

 mander Boulton, R.N., that there is a large abnormal deviation of the compass. The 

 line above indicated measiires thousands of miles in length, and, as will be observed, it is 

 almost straight. The fact, that the axis of the Cincinnati anticlinal lies in direct continua- 

 tion of this long chain of geological and geographical features, is probably luore than a 

 chance coincidence, as the latter may well be supposed to have constituted a line of weak- 

 ness which would be effected by any east and west movement or force in the crust of the 

 earth, and slight, but jjersistent, elevations of the Palaeozoic strata south of the Archaean 

 area may have easily taken place along its course, and these disturbances may have oc- 

 curred at different geological periods, as some of the above mentioned facts would seem to 

 indicate. 



Leaving the subject of the cause and general course of the Cincinnati anticlinal, some 

 practical results may be obtained by a study of the peculiarities or details of this great 

 arch. The trend of its crown varies locally, of course, but the geological distribution of 

 the formations at the surface shew that this axis, coming northward from Kentucky an 

 passing under the town of Findlay, would strike the south shore of Lake Erie about mid- 

 way between Toledo and Port Clinton ; but in this vicinity the general wave is divided by 

 a small synclinal into two subordinate anticlinals. Professor Orton has shewn, by the re- 

 sult of borings, that the form of the Trenton area in north-western Ohio, as indicated by a 

 horizontal plane at 500 feet below the sea level, wovild prove that the axis at that depth 

 points directly towards Toledo. Notwithstanding the difference in the courses of the 

 deeply seated and surface folds, the main axis of the anticlinal will intersect the north 

 shore of Lake Erie in the vicinity of Little's Point, in the county of Essex ; then running 

 about north-north-east through Essex, Bothwell and Lambton, it will reach the southern 

 shore of Lake Huron near Kettle Point. Its general bearing from Lake Erie to Lake 

 Huron is about N. 30° E., but it appears to curve gently to the south-east of a straight line 

 and to pass under Petrolia. 



South of the edge of the Archaean nucleus, which forms the north shore of Lake Huron 

 and Greorgian Bay, the axes of the numerous anticlinals in the Palaeozoic strata run south 

 and south-west and their average course corresponds with that of the Cincinnati anticlinal, 

 but as we recede from the outcrop of the ancient rocks, and the newer strata deepen over 

 them, the inequalities in the old foundation become covered up and more and more ob- 

 literated, and smaller undulations running in other directions manifest themselves. The 

 Cincinnati anticlinal in south-western Ontario, as elsewhere, is a gentle swell of great 

 breadth, but within its general area, and especially near the summit, are minor anti- 

 clinals, sometimes of a sharper form, running both parallel with and transverse to its gen- 

 eral course. One of these secondary anticlinals, having the former course, is shewn to 



