GEOLOGICAL AND NATURAL HISTORY SURVEYS. 165 



the opposite of that on the northerly and eastorly slopes, for this 

 latter district is constantly subject to the chilling influence of the 

 northerly winds from Lake Superior." 



In considering the rocks of the northern part of the Peninsula he 

 writes that they " tnay be regarded as referable to the great car- 

 boniferous group of the State, a position to which their fossil con- 

 tents is amply sufficient to substantiate their claim"; but he makes 

 no paleontological citations in evidence. " In this respect," he con- 

 tinues, " they coincide with the rocks heretofore described as occupy- 

 ing the southern counties; nevertheless it must be borne in mind, as 

 there stated, that these rocks occupy a very different position in the 

 series." It does not appear, however, whether he considered the 

 position higher or lower. " The line of bearing " of the strata, " not 

 only in the northern, but likewise in the southern portion of the 

 peninsula, is regularly northeasterly and southwesterly." As a fur- 

 ther conclusion, he infers " that the coal of tlie central portions of 

 our State and that upon the Illinois River is embraced in a rock 

 which belongs to the same portion of the great basin " — a conclusion 

 which, if borne out, will aid nnich in determining some important 

 points respecting the relation which the neighboring rocks bear to 

 each other (p. 9). It does not appear whether the "great basin" 

 here referred to is the hydrographic basin of the Mississippi or a 

 great coal basin, nor is it apparent what the " important points " are. 



In a similar vein he expresses the conclusion that " that portion of 

 the rock series Avhich in Illinois and Wisconsin embraces the ores of 

 lead is identical with a portion of the rock formation which occurs 

 in the northern part of our own State — a circumstance which might 

 fairlv have been inferred from the general line of bearing of the 

 rock" (pp. 9-10). He regards Saginaw Bay as lying in the same 

 " line of bearing" and " occupying a denuded space in the sandstone 

 just at that point where the latter comes in contact with the linie- 

 stone of the north." lie does not indicate, however, which he re- 

 gards as tlie overlying formation. He proceeds to describe with the 

 accuracy of a sagacious observer the various kinds of strata appear- 

 ing at the surface from Point aux Bargues to Mackinac, but he does 

 not discover that limestones of different ages pass under review. 

 The bituminous shale of Sulphur Island did not escape him, but he 

 recorded it as " di]:>ping below the limestone ju.st described." which 

 is that of " the southerly cape of Thunder Bay " (p. 11). 



All the localities of limestone, now well known, from Saginaw 

 Bay to the Straits, in the vicinity of the shore, are indicated in this 

 report, and the author gives a correct account of the brecciated mass 

 of Mackinac Island. But he does not state that the limestonps hold 



