.General Description of Lake Erie. 377 



remains are not so plentiful ; but are of the same kind. West 

 of Grand River, the limestone only seemed to differ in the 

 diminished proportion of chertz, this substance, however, 

 being still disposed in the same manner as before. The fossils 

 here are both of chertz and granular carbonate of lime. The 

 turbinoliai differ much in their size. They are all fragments, 

 and they are of a tapering form. Two feet are here a common, 

 but I believe hitherto an unexampled, length. They are often 

 only as many inches. The greatest diameter that I met with 

 was four inches. They are of very various shapes ; as straight, 

 gently or very much curved, and they frequently are bent 

 suddenly at right angles, which I have never seen anywhere 

 else. The coral often occupies many square feet of the rock, 

 and are either placed vertically, or radiate from a centre. 

 Common cellular madrepore, in round balls of radiating cells, 

 2 to 12 inches in diameter, are frequent. Millepore coral, of 

 large size and length, with triangular foramina, is very common, 

 as are^ incrinites. I met with a few producti similar to the P. 

 lobatus of Sowerby. PI. 418. 



This chertzy limestone is sufficiently described in the above 

 paragraphs *. According to Mr. Eaton, it is repeatedly seen 

 in the state of New York. Its connexion with the inferior 

 rocks in Lake Erie has not been investigated, and, I believe, 

 is completely concealed ; but at Black Rock, close at hand, 

 we have seen it to cease suddenly, and to rest in some places 

 on pudding-stone. I consider it and the next rock below to 

 be deposited nearly at the same time ; from their conformable- 

 ness, the similarity of their contents, and from the small 

 quantity and partial distribution of the pudding-stone. 



Of the brown limestone in the middle of the south shore 

 of this lake, I know very little. I have seen it frequently from 

 a short distance, bounding the lake in pretty thick horizontal 

 layers. Mr. Maclure visited it many years ago ; and found 

 caryophyllites and large terebratulae in it. Eight miles east of 



* Sir Peregrine Maitland mentioned to me, that a considerable vein 

 of galena is found in the banks of the Grand River, 50 to GO miles up. 

 It is possibly in this limes lone, as the river, to its head, passes over 

 calcareous rocks. 



