*Y. fV. Portion of Lake Huron. 269 



The other long side possesses the same geological fea- 

 tures as the one just described. The breccia perhaps 

 abounds more here. The slaty portions are found at every 

 level and at one place in strata two feet thick. About the 

 middle there is a cave, about three yards in its great- 

 est depth, formed by the concurrence of several of the cav- 

 ernous, bowl-shaped hollows, thus creating one of great di- 

 mensions; whose interior is subdivided into smaller cavities 

 seriatim. 



The beach is covered almost exclusively with limestones 

 slaty, vesicular and brecciated. I saw the vesicular species 

 after it had been exposed to the heat of a kiln. It had suf- 

 fered a change of colour only from its ochry yellow, to a 

 brown or black. 



The stratified limestone burns profitably. 



TwO; if not three eras and modes of formation are here 

 clearly distinguishable. The first and oldest is the slate, 

 which is seen to floor the lake for miles around. Upon it 

 are supported two calcareous masses which mingle with 

 each other and with short slips of the schist in the greatest 

 disorder ; and having a few of the broken flints interspers- 

 ed. In all probability they are veins of strata which have 

 been overwhelmed by a sudden violent force. 



Heat may have been the means of raising, comminuting, 

 and partially melting this bed of limestone. Steam, a prin- 

 cipal agent, may have insinuated itself into the more yield- 

 ing portions ; and the whole, has finally, consolidated. ^ 



Appendix. 



As this paper has already assumed an inconvenient size. 

 I shall content myself with noticing in the briefest manner 

 possible, the conglomerates, and a mineral with which I am 

 acquainted. The description of the organic remains, must 

 also be greatly limited. 



The conglomerates are curious, and are met with prin- 

 cipally in the shape of debris. Their matrices are of two 

 kinds, quartz and greenstone. The quartzose species ex- 

 hibits three forms — its nodules are sometimes exclusively, 

 translucent white quartz. In other instances they are mass- 

 es of greenstone; but by far more commonly they are of 



