HURON COUNTY. 309 



^ HAMILTON GROUP. 



This important group of limestones and shales of the New York geolo- 

 gists is here represented by a thin and unimportant deposit of bluish 

 yellow marly limestone. This is quite soluble, and therefore much honey- 

 combed and eroded at its points of exposure. Were it not for the profusion 

 of Hamilton fossils contained in it, this would be regarded as the upper 

 part of the Corniferous limestone, upon which it rests. It is apparently 

 only from ten to fifteen feet in thickness, in thin layers, containing a 

 profusion of crinoid stems, and its outcrops in this county afford no ma- 

 terial for adding any thing to the description given by Prof. Newberry 

 in the first volume of this report. 



COHNIFEROUS LIMESTONE. 



This formation contributes the surface rock at Bellevue, and a small 

 territory adjacent in the north-west part of the county. Two and a half 

 miles north of the village, and on the county line, it is covered with only 

 from eighteen inches to two feet of soil, and has been exposed in a quarry 

 to the depth of eight feet. The rock is in thin layers, hard, compact, 

 highly fossiliferous, and presenting the ordinary characteristics of the up- 

 per layers of the Corniferous at Sandusky. Its surface is thirty feet above 

 the railway at Bellevue. South from this point, and three-fourths of a mile 

 north of the south line of Lyme township, it is struck as the first rock in 

 sinking wells at a depth of 12 feet from the surface. Still further south, and 

 west of Weaver's Corners, a ridge of limestone soil, filled with its debris, 

 crosses the west line of the county at an elevation of fifty feet above 

 Bellevue, making the thickness of this rock in the county approximately 

 fifty feet. Near the north line of Sherman township, on the old Colum- 

 bus and Sandusky turnpike, the Huron shale is struck in sinking wells, 

 showing that the corniferous limestone covers only a small part of Lyme 

 and a mere corner of Sherman townships. Exposures in the county 

 afford very imperfect opportunities for the study of this formation, which 

 is sufficiently described in the reports upon other counties. 



