62 LOWER PENINSULA. 



superposition, which can not be distinguished if found in different 

 localitcs, unless the sections exhibit the strata fully denuded 

 so that their relative positions to other strata and to one another 

 maybe observed. The strata have retained their original position, 

 but their horizontality is not perfect ; they rise and sink in undula- 

 tions, adapting themselves to the surface on which they were de- 

 posited. By means of these undulations, lower or higher strata 

 come repeatedly to an exposure, or disappear again, if we follow the 

 horizontal level of the shore line of the bay, which approximately 

 runs parallel with the strike of the formation., and would consequent- 

 ly always present the same rock beds if the strata remained per- 

 fectly horizontal. I estimate the thickness of the exposed rock beds 

 at from 125 to 130 feet. In the bluffs near Bear Creek, where we see 

 the upper part of the series, 45 feet of rock beds are exposed in 

 direct, vertical superposition, and by the slight rise of the strata 

 toward the east, about 10 feet more of lower beds come to the 

 surface. A continuation of this section downward is offered on 

 Bear Creek, where we see, near the railroad bridge, some beds 

 representing the rock of the bluffs, without being able to ascer- 

 tain exactly which part of them. At all events, in the interval 

 from the bridge to Porter's mill, about 15 feet of strata, lower 

 than any in the bluffs, can be seen ; then follow 6 or 8 feet 

 of blue shale, and below are again limestones amounting to 

 about 20 feet in thickness, reaching the base of Ingall's mill- 

 race. Lower down the section can not be followed, but we find 

 the same strata seen at Ingall's mill on the shore exposures west 

 from the mouth of the river, which beds, all added, make a series 

 of something over 100 feet in thickness. If we add to them the 

 25 feet of strata seen in the exposures of Norwood, which are 

 higher than any of the others, we have an estimated total thick- 

 ness of 125 feet, which estimate maybe perhaps as little lower 

 than the actual measurement would give. The direct superposi- 

 tion of the rock series of the Norwood exposures on the dolomites 

 of Bear Creek bluffs or of Khagashewung Point is not seen ; an 

 interval of several miles separates the outcrops, which may hide 

 some intervening ledges under its drift cover. 



The Hamilton exposures on the east and west side of the penin- 

 sula exhibit not enough of lithological similarity to allow an iden- 

 tification of certain beds or groups of beds on the two sides ; also 



