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 Prot. Newberry 
in the first volume of this report. 
CORNIFEROUS 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. Hxposures in the county 
afford very imperfect opportunities for the study of this formation, which 
is sufficiently described in the reports upon other counties. 
