244 CAA'ES AND POTHOLES AT ROCKWOOD. 



THE CAVES AND POTHOLES AT ROCKWOOD, 



ONTARIO. 



BY PROF. J. HOYES PAXTOX, M. A., F. G. S. 



Some time ago while on a trip to Rockwood, with students of 

 Geology from the Agricultural C^ollege, for the purpose of showing 

 them some e.xamples of how water acts ui)on limestone I was forcibly 

 impressed by a most interesting series of Potholes found in that 

 district, not far from where the somewhat well known cav^es are seen. 



So impressive were these phenomei^a, that for three consecutive 

 holidays, the students made their way to Rockwood, and on two of 

 the occasions, were accompanied by myst^lf. 



A thorough examination of the locality was made, and data collect- 

 ed, which I purpose placing before you this evening, and which should 

 be interesting to a Society that has been established for the purpose 

 of developing the history of our Province whether it be written upon 

 the rocks or pages of a more perishable character. 



In treating the subject, the following divisions are naturally pre- 

 sented : — 1. The location of the Caves and Potholes ; 2. A description 

 of them ; 3. An explanation of their formation ; 4. Theories concern- 

 ing the oiigin of the phenomena, that caused their formation. 



1. — Location. 



Rockwood is a small village on the line of the Grand Trunk Rail- 

 way, situated about 8 mUes east of Guelph, and 42 west of Toronto. 

 Leaving the station and proceeding in the direction of the village, 

 you very soon observe that you are in a place well named — Rockwood, 

 from the amount of rock in the vicinity. Along the river, which 

 passes through the village are striking exposures of rock, at some 

 places escarpments 50 to 70 feet high made u[) largely of massive 

 layers of Magnesian limestone, belonging to the Niagai'a formation of 

 the Silurian system. Fossils are not numerous, Crinoid stems are by 



