376: General Description of Lake Erie. 



have subsequently disappeared. These impressions are small, 

 and are distributed in thin horizontal layers. This pale stratum 

 ceases suddenly upwards, and, in a few parts, is replaced at 

 once by a calcareous pudding-stone, coated and penetrated by 

 a coppery-green substance. The nodules are small, and too 

 much altered for me to ascertain the stratum to which they 

 might belong. I saw them in 1824. The extensive works 

 now carried on at Black Rock may have, by this time, laid 

 open a larger and less disintegrated portion of this pudding- 

 stone. The most common covering of the pale limestone is 

 a black shale, usually six inches thick, horizontal, with gentle 

 undulations ; succeeded by a dark-brown limestone, with dark 

 chertz ; at first in small kidneys, which soon coalesce and 

 form lumps, strings, and finally flakes and layers of irregular 

 thickness, and with a waving horizontality. The chertz, 

 sometimes pale, increases in quantity upwards, until (near the 

 level of the village) it becomes the greatest part of the rock, 

 in thick shining seams, of almost pure flint ; the calcareous 

 intervals also containing small masses of chertz. Some of 

 the larger knots of chertz shew a distinct madreporic structure, 

 with small cells. Interspersed in the calcareous portions are 

 producti, terebratulse, corallines, various retepores, turbinoiae, 

 all composed of chertzy. I have seen a calymene (Blumenb..^) 

 from this rock. Some hundred yards above the spot where I 

 made the above observations, the chertzy limestone is at the 

 water-mark ; a fact accounted for by the difference of level at 

 the two places, assisted, perhaps, by a slight dip in the rock 

 itself. 



This kind of limestone I carefully traced from Black Rock, 

 along the north shore of Lake Erie for 55 miles, and from the 

 nature of the country was enabled to see that, for several miles 

 westward, no remarkable change took place. About, and for 

 a few miles to the west of Fort Erie, the rock is excessively 

 charged with flint, great portions of which being interspersed 

 with the fossils occurring at Black Rock. Captain Bolton, 

 R.E., shewed me some fine trilobites, and a trochus from this 

 place. On the way to Grand River it becomes paler occasion- 

 ally, and varies much in the amount of its chertz. From 

 Forsyth's Point to Steel's Tavern, (seven miles) the organic 



