Qm&ral Description of Lake Erie, 375 



on the left, irregularly oval, horizontally depressed above, lips 

 not reflected. 



II. M. bicarinata. Whorls acutely carinated on the middle 

 above, and obsoletely carinated beneath. — Journal of Nat. 

 Science, Philad. vol. i. p. 311. 



The shale ** embraces numerous globular concretions^ con- 

 sisting chiefly of a kind of wacke. 



" On breaking a great number of them, which were from an 

 inch to a foot in diameter, I found that they all contained some 

 sort of nucleus different from the inclosing matter. The nu- 

 cleus is frequently the irregular fragment of a petrifaction ; 

 sometimes of limestone, very unlike that variety which is con- 

 nected with this stratum in layers." {Eaton, p. 145.) The 

 iron pyrites ** is mostly attached to the under surface of the 

 layers, in a stalactitic or mammillary form. It is a bright 

 golden yellow coating, and forms immense quantities of petri- 

 factions." (P. 1440 



This Well characterized rock is seen at Black Rock, on the 

 River Niagara, to rest upon the chertzy limestone, next to be 

 described, which prevails on the north shore of Lake Erie for 

 at least 55 miles from that river ; but only in platforms and a 

 few ledges. Whether the transition be sudden or gradual, I 

 am unable to say, never having seen the pyritous shale. This 

 limestone, denominated by Mr. Eaton " cornitiferous," is 

 finely displayed at Black Rock, near the head of the River 

 Niagara. At this village the river bank is a low cliff, sur- 

 mounted by a rough, steep, grassy slope, cut through, near 

 Major Eraser's house, by the channel of a creek. Just above 

 the ferry here, there are, at water-mark, or a little above, 

 six feet of fine grained blue and pale brown, very conchoidal 

 limestone, without chertz or other foreign matters ; then 

 gradually horizontal streaks, of a pale grey colour, appear in 

 the limestone, which, rapidly increasing in number and size, 

 produce, for nine feet higher, a very pale brown rock, filled 

 with small geodes of copper pyrites, calcspar, and a large 

 quantity of foliated strontian, imbedded in thin angular masses 

 of a white colour. 1 observed, in this part of the cliff, several 

 small producti ; but the most numerous traces of animal life 

 are the cavities impressed by the casts of turbinoUae, which 



