378 General Description of Lake Erie. 



Cleaveland, there is, a little way from the lake, and some feet 

 above its level, some strata of greyish-white sandstone, rather 

 fine-grained, and moderately hard. It is used for grindstones. ' 

 I saw no organic remains in the fragments shewn to me. I had 

 no opportunity of ascertaining its relations with the calcareous 

 rocks around. 



The limestone of the head of the lake, including Sandusky 

 Bay and Peninsula, Put-in-bay islands, the mouth of the River 

 Detroit, and its contiguous islands, Celeron and Grosse Isle, is 

 nearly the same everywhere. Its relative age is rendered 

 doubtful by its not having yet been seen in juxtaposition with 

 other rocks, and by the little aid afforded by its mineral and 

 fossil contents. The following circumstances, however, seem 

 to place it just above the sandstones connected with the salt 

 formation. These are, its mineralogical resemblance to a rock 

 on the River Niagara, of known relations, its containing consi- 

 derable quantities of gypsum, the proximity of salt springs, and 

 its great remoteness from primitive formations, 280 to 300 

 miles. 



It is of a pale grey, or of a greyish straw colour, homoge- 

 neous, granular, and rather soft. It is in thick, apparently hori- 

 zontal layers, and is seldom slaty. It is occasionally cavernous. 

 In the immediate vicinity of masses of strontian, the specific 

 gravity is sometimes 3 and 3.3, and then it is of a white colour. 

 In other places, it is, as usual, about 2.6. Mr. Bird, Astro- 

 nomer to the Boundary Commission, met with a gray limestone 

 here, which was perfectly dry, and nearly inodorous, when 

 cold, but which, when warmed, became covered with a slight 

 exudation of petroleum, and had the smell peculiar to that 

 substance. 



The Bass islands contain a cave, which is entered by a round 

 hole a yard wide, gradually widening for 50 feet, when it opens 

 into a circular space 100 feet in diameter and 7 feet high. 

 The roof is studded with brown stalactites, frequently hollow, 

 and seldom more than three-fourths of an inch thick, or longer 

 than three inches. The floor is covered in a similar manner*. 



* This account I received when near the place, in 1819, from Lieut, 

 Dix, aide-de-camp to the American General, Brown. 



