OF UPPER CANADA AND THE WESTERN PART OF OHIO. 277 



At Paris it is associated, we have already said, with the gypsum-bearing 

 shales. From that neighbourhood it may be traced northward to the vicinity 

 of Guelph, in obedience to the general northern strike of all the rocks as they 

 follow the trend of the great terrace. Westward and south-westward from 

 Guelph the stratum very gently declines in level, in accordance with the 

 general dip. At Beachville, on the south branch of the Thames, it is below 

 the level of the water, the river bed, both here and at intervals for many miles 

 north-eastward, exposing a higher limestone, and on the north branch of the 

 same river we ascend the stream nearly forty miles northward from London 

 before the pitted rock emerges to the surface. South of a nearly east and west 

 line, drawn from Guelph to Goderich, rounded and weather-worn fragments of 

 the pitted rock abound in the general drift, composed of the limestones and 

 other beds that outcrop to the north and north-east. But in the Maitland river 

 of Lake Huron, it is found in situ, well exposed with a group of overlying 

 limestones both at Goderich and for several miles up the stream. 



Li no instance either among the rolled fragments or in the beds seen in 

 place, did we detect any organic remains ; but its position at the top of the 

 gypseous shales, and its singularly well marked features, leave us in no uncer- 

 tainty as to the formation to which it belongs. 



Of the Rocks overlying the Vesicular Limestone in Upper Canada. — The 

 strata which repose upon the pitted, or vesicular limestone in the western 

 portions of Upper Canada, do not accord, exactly, with those which overlie 

 this rock in New York. Important changes in the group take place, in fact, 

 within the limits of that State, and other modifications will be shown to arise 

 westward of the Niagara River. In the central counties of New York, the 

 following strata, according to Mr. Vanuxem, intervene between the pitted rock 

 and the Marcellus shales. 1. Hydraulic limestone; 2. Pentamerus limestone; 

 3. Delthyris shaly limestone ; 4. Scutella limestone; 5. Oriskany sandstone; 

 6. Fucoides Cauda Galli beds; 7. Onondaga limestone; 8. Corniferous lime- 

 stone; 9. Seneca limestone.* But in the counties west of the Genessee River 

 the only strata not thinned away are, 1. Hydraulic limestone. 5. Oriskany 

 sandstone. 7. Onondaga limestone. 8. Corniferous limestone, and 9. Seneca 

 limestone. t Some of these remaining strata are much lessened in thickness, 



* See Vanuxem's fourth Annual Report, General Survey of New York. 

 t See Hall's fourth Annual Report, General Survey of New York. 



