cliv PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



the reports of the Michigan Surveyors as 578 feet ; and the bottom 

 of that lake is doubtless, as I formerly observed, in many parts 

 below the surf ace -level of the ocean, whilst other lakes occur at the 

 level of 1400, 1300, 1200, and all the intervening levels, down to 

 Hound Lake, 521, or nearly 60 feet below Lake Huron, and Chats 

 Lake, 233, — the country rising to the north, and falling eastwards 

 to the Ottawa. The Laurcntine series of gneiss and crystalline 

 limestone occurs here fully developed, and is overlaid by patches 

 of Lower Silurian shale ; and Mr. Murray seems, from the fossils 

 contained in some of the beds, to have recognized some portions 

 of the series of four beds (Calciferous sandstone, Chazy limestone, 

 Birdseye limestone, Trenton limestone) which follow the Potsdam 

 sandstone. In further investigations, when he had the valuable 

 assistance of Professor James Hall of New York, he carried the 

 ancient rocks of "Western Canada a little higher up, to the Trenton 

 limestone and TJtica slate, or nearly to the upper limit of the Lower 

 Silurian. 



Mr. James Richardson, another assistant-geologist, conducted the 

 inquiries more to the east. Here, supposing that the Mingan 

 Islands may be assumed to exhibit the lower or basic member (that 

 is, the Laurentine system), Harbour Island the calciferous sandstone, 

 Large Island the Chazy and part of the Birdseye formations, and 

 the sea-interval to be occupied by a succession of strata about 1700 

 feet thick (assumed to be equivalent to the upper part of the 

 Birdseye limestone, the Trenton formation, the Utica slates, and 

 the lower portion of the Hudson-River group), the Anticosti rocks 

 are formed into six divisions, of which the lower portion is con- 

 sidered by Mr. Billings to belong to the Hudson-River group, the 

 middle as merging into the Clinton, and being more in conformity 

 stratigraphically with the Oneida conglomerate and Medina sand- 

 stones, that is, distinctly transitional or Middle Silurian, Mr. Billings 

 having adopted that term in anticipation of Dr. Bigsby. The upper 

 section passes into the Upper Silurian ; so that the whole series is 

 here exhibited in a very moderate space. Mr. Billings has given 

 lists of the fossils found in all these beds ; and Dr. Bigsby's paper 

 will be of great use in comparing them with the lists given by the 

 United States geologists. The geological reports are concluded by 

 a description of many new Canadian fossils by Mr. Billings, in which 

 the great number of new species of Crinoicls, of Cystidese, and of 

 Asteriadae is very remarkable. A new species is added to the genus 

 Bronteus or Brontes of Goldfuss, as also one to the genus Triarthrus 

 of Greene ; and I may add, that here, as everywhere, the Calymene 

 Blumenbacliii appears to link together all the members of the Si- 

 lurian, and, in my opinion, did it stand alone, would prove their 

 identity as parts of one great natural-history system*. The final 

 reports are chemical and mineralogical, by Mr. Hunt, the Chemist 

 and Mineralogist of the Canadian Geological Survey. 



In the United States there has been no cessation of that activity 



* As yet no figures of these fossils have been published. 



