I2S 



Cincinnati Society of Natural History. 



some 350 miles to the eastward. Even in Canada and the 

 eastern States, where it is known as the Chazy, it occupies 

 scattered patches, which are limited in area. On the map 

 referred to above, the sandstone on the south shore of Lake 

 Superior, and the outcrops of St. Peter's in Wisconsin and 

 Minnesota, are colored as Chazy ; and in another map in the 

 same atlas, showing the distribution of the Huronian rocks, 

 by Sir W. E. Logan, the distribution of the sandstone is 

 given in more detail, and it is designated in the legend as 

 " Chazy (St. Peter's Sandstone). 1 ' 



The reference of the St. Peter's to the horizon of the Chazy 

 has been made by various writers, solely, it would appear, 

 upon stratigraphic evidence. Hall, in 1863,* considered it as 

 the equivalent of the Chazy. He says: " So long since as 

 1845, I had myself observed that the sandstones of the St. 

 Mary's River come out from beneath the Black River and 

 Birdseye limestones ; but the Calciferous sandstone was no- 

 where visible in the immediate neighborhood. The later and 

 more complete investigations of the Canada Geological Sur- 

 vey have proved the absence of the Calciferous sandstone, 

 and of the Potsdam sandstone, on the north shore of Lake 

 Huron ; and, also, that this sandstone of St. Mary's River 

 (which is now regarded as identical with that of the south 

 shore of Lake Superior), rises from beneath the Black River 

 and Birdseye limestone, and there is no evidence of the Cal- 

 ciferous sandstone in that region. It is the opinion of Sir 

 William Logan, that this sandstone represents the Upper 

 sandstone, or fills the place of the Chazy formation in the 

 East, the limestone being absent ; and that it is this arena- 

 ceous deposit, greatly augmented, which gives the sandstone 

 formation of the south shore of Lake Superior (Geology of 

 Canada, 1863, pp. 83-86)." 



After giving the sequence of the formations as found in the 

 Mississippi valley, as Buff limestone- Birdseye and Black 

 River ; St. Peter's sandstone ; Lower Magnesian limestone, 

 he says : " In assigning a position to the sandstone of the 

 south shore of Lake Superior, to the south and east of 

 Keweena point, from the evidence before us, and in the 

 absence of any fossils which may aid the decision, we are 



♦Sixteenth Ann. Kept. N. Y. State Cab. Nat. Hist., pp. 214-215. 



