342 



THE GEOLOGIST. 



Taking the two classes together as representing thirty distinct 

 series of cavernous locahties, one is found in the 'New Red Sandstone 

 formation, two in the Carboniferous, two in the Devonian or Old 

 Red, seven in the limestones of the Upper, two in those of the 

 Middle, and six in those of the Lower Silurian formation, three in 

 the Huronian rocks of Sir William Logan, and seven in the Lauren- 

 tian rocks of the same geologist. In the last of these they are pre- 

 sent in the interstratified bands of crystalline limestone, characteristic 

 of this formation in Canada. 



With a few exceptions nearly all occur in limestone rocks, and 

 their origin has depended upon various causes. The first fourteen, 

 which compose the first division, enumerated in a previous part of 

 this paper, are the results of aqueous action, as their situation, present 

 condition, and general description clearly prove. Perhaps an ex- 

 ception might be taken to the formation of pilasters and gothic 

 arched recesses, which are more properly attributable to atmospheric 

 influences. Volcanic agency has given origin to the basaltic dykes 

 of Mecattina (17), the basalt of Henley Island (16), Bouchette's 

 (19), and Gibb's (20) caverns. The same cause has most likely in- 

 fluenced the subterraneous passages of Manitoulin (28), and Murray's 

 Cavern (29). On the other hand, Bigsby's Cavern (18), Colqu- 

 lioun's (22), the Mono and Eramosa (25 and 26), and Bass Island's 

 Caverns (27) were formed by some other agency, in which a slow 

 disintegration of the rocks has occurred from chemical and other 

 causes, and the soluble particles have been removed by the influence 

 of water, entering by percolation from above, or between the neigh- 

 bouring layers of rock. The origin of the Quartz Cavern, by the ex- 

 plosion of a pyritous vein (23), is clear enough. 



It would be premature to enter at further length into the con- 

 sideration of the formation of these caverns until farther evidence 

 has been obtained. It is hoped, however, that this first attempt to 

 embody a descriptive and connected account of the caverns of 

 Canada in a single paper will be productive of ultimate good results 

 to science, by stimulating the zeal of those on the spot to carry out 

 by further exploration an earnest investigation of this interesting 

 subject, for there is still much to be done to render it complete. 

 Many of the caverns are s^^stematically noticed and described for the 

 first time ; and before this memoir was written, the inhabitants of 

 that country were hardly aware that any caverns existed at all, except 

 the comparatively few residing in the immediate neighbom-hood of 

 their presence. 



