Revieics — Dr. G. M. Darcson's Borings in Manitoba. 279 



while evidently representing the Boulder-clay, is unusually pale in 

 colour, being apparently composed of limestone debris." 



Passing on to the consideration of the beds underlying the drift, 

 we learn that their geological age was considered by the author to be 

 doubtful, owing to the entire absence of palseontological evidence or 

 of any outcrops in the vicinity of the boring, by which the result of 

 the operations might have been checked. 



However, pretty strong presumptive evidence seems to have been 

 elicited regarding the age of the beds supposed to represent the 

 "Maquoketa shales," so named by Dr. C. A. White, in Iowa. In 

 Iowa these shales are about 75 feet in thickness, and consist of 

 bluish and brownish shales with calcareous layers. In Wisconsin, 

 they average about 200 feet in thickness, and are composed of grey, 

 green, blue, red, purple, buff and brown shales with thin limestones. 

 These beds are met with also in Minnesota, but owing to the want 

 of complete sections they could not be compared with those of the 

 Eosenfeld boring. But at Stony Mountain, Manitoba, fifty-eight 

 miles north, strata determined by their fossils to be of the horizon 

 of the Hudson Eiver were met with. A section made at this locality 

 showed that the rocks consisted of dolomitic and other limestones, 

 and red and yellow shales, resembling very closely those referred to 

 the Maquoketa Shales (Nos. 10 to 13 in the section) in the Eosenfeld 

 boring. 



The limestone (No. 14) underlying the Maquoketa shales is 

 assigned to the horizon of the Galena limestone of the west, which, 

 it was found to resemble in character ; while the red shale at the 

 base (No. 15) was supposed to be the equivalent of the Trenton. 



" The Galena limestone of the West, which is nearly equivalent 

 to the Utica of the New York series, is about 180 feet thick in 

 Minnesota ; 250 feet thick in Wisconsin ; and from 100 to 250 feet 

 thick in Iowa. 



" The Trenton in Minnesota consists of flaggy limestones, with, 

 interbedded greenish shales, and is nearly 160 feet in thickness. In 

 Iowa it consists of clayey shales and shaly and compact limestone, 

 200 feet in thickness. The reddish colours of the Eosenfeld shales- 

 and their apparently more complete separation from the limestone 

 and want of interlamination with it, constitute the chief point of 

 dissimilarity. The massive buff limestones of Selkirk and Stone 

 Fort in Manitoba, resemble the Eosenfeld bed in character, and are 

 known by the evidence of fossils to represent the Galena." 



No. 16 in the section, an " unconsolidated sand-bed," is described aa 

 resembling precisely the " St. Peter Sandstone," as typically developed 

 near St. Paul, Minnesota. 



Assuming that the geological horizons of the preceding beds have 

 been accurately determined, then it is held that beds 17 to 20 (both 

 inclusive) must be referred to the " Lower Magnesian Limestone," 

 equivalent in age to the Calciferous [Tremadoc] of the New York 

 section. This limestone in Iowa and Wisconsin has a thickness of 

 65 to 250 feet. In Minnesota it is a magnesian rock, sandy towards 

 the top, and with beds of greenish shale. At Eosenfeld there is no 



