6o LOWER PENINSULA. 



in this locality very fossiliferous. There are : Spirifer pennatus, 

 Chonetes Emmctensis, Strophodonta nacrea, and all the other 

 fossils enumerated previously as existing in equivalent beds 

 exposed west of Khagashewung Point and east of Charlevoix. 

 From the frequent occurrence of a species of Stictopora in these 

 beds, Prof. Winchell termed them Bryozoa beds. The shore line 

 has here a north and south direction. Three miles south of the 

 locality just treated of, some other exposures are found, and at 

 about five miles from it we see the Hamilton group for the last 

 time, exposed near Norwood. 



The beds at Norwood are higher than any of those in the sec- 

 tions yet described. In the bluffs which have about 12 feet eleva- 

 tion above the water level, we can observe about 25 feet of strata 

 brought to the surface by an undulation. Lowest are dark, bluish 

 gray, rough-fracturing limestones, with intermediate seams of shale, 

 inclosing many specimens of Favosites. Above are thinly bedded, 

 hard limestones, alternating with ledges or nodular seams of flint 

 limestone, and flint beds of a laminated, banded structure ; their 

 thickness is about 8 feet. Some thicker ledges of limestone follow, 

 having a smooth, conchoidal fracture. Next higher are gray, 

 compact limestones with many fossils : Stromatopora similar to 

 Str. Wortheni, Caunopora (thin stems with a ventral canal, of 

 thickness from a straw to a goose-quill), Favosites Hamiltonensis, 

 Favosites digitatus, Cyathophyllum Houghtoni, Cyathophyllum 

 geniculatum, Aulopora, Strophodonta erratica, Pentamerus (a 

 large, globose form), and several others. The highest strata are 

 coarse-grained, crystalline dolomites, of light gray color, some 4 or 5 

 feet in thickness, which contain Stromatopora and other fossils 

 in very imperfect preservation, while numerous druse cavities, 

 once the beds of fossils, are lined with spar crystals and partially 

 filled with rock oil. 



A chemical analysis of the dolomite gave : 



Carbonate of lime 56 per cent. 



" magnesia 39 " 



Alumina and iron 2.8 " 



Insoluble residue 0.4 " 



In immediate superposition on the dolomite beds, the black shale 



