82 REPORT OF THE 



which occurs a Bhyrwhonella (n, sp.) and the Bellerophon, so abun- 

 dant in the Marshall sandstone, which I have named B. galeri- 

 culaius. 



At the first small point east of Burnt Cabin Pt., a greenish 

 blue sandstone is seen rising to the surface and forming a bluff 

 8 feet high. This rock contains the Clymenia of the grindstone 

 quarries, a mile* further east, and with care may be traced to 

 that point where it is found overlain by a conglomerate 2 feet 

 thick, apparently forming the base of the group. 



Such is a general description of the sandstones of the coast 

 of Huron county, from the highest beds containing Nucula to 

 the conglomerate above the gritstones, both included. It has 

 not been deemed proper to occupy space with the details of 

 stratification at the several points at the present time. 



The rocks of this group, as well as those of the Napoleen and 

 Huron Groups, should make their appearance again on the 

 opposite side of Saginaw Bay, between Thunder Bay and Ot- 

 tawa Pt. This whole coast is, however, destitute of a single 

 outcrop. Nevertheless, the great accumulation of sand along 

 the beach, and the well known arenaceous character of the 

 country further west, affords a sufficiently strong presumption 

 that the limits stated cover the place of outcrop of these 

 groups. 



In Sanilac county, near the head waters of the Cass river, 

 sandrock is exposed to a considerable extent, which undoubt- 

 edly belongs to the Huron county series. On the S. E. J sec. 

 7, T. 13 N., 12 E., are found numerous fragments of a coarse, 

 gray, micaceous sandrock, sometimes inclining to greenish, and 

 sometimes mottled or striped with red. Many of these frag- 

 ments contain white quartzose pebbles, and the whole aspect 

 of the rock recalls that seen at Pt. au Pain Sucre. From this 

 point actual outcrops are frequent as far down the stream as 

 the line of Tuscola county, and even to S. W. \ sec. 1, T. 13 

 N., 11 E., where it rises 5 \ feet above the water. The general 

 character of the rock is shown by the following section on sec. 

 1, T. 13 N., 18 E.: 



