614 REPORT UNITED STATES GEOLOGICAL SURVEY. 



our examination of this range was too cursory to enable us to present a 

 section, as only the upper part of the series was seen here by us. North- 

 west of the Bear River Range there are larger areas of Silurian rocks, 

 the ranges in that region being largely composed of them. It is a region 

 of complicated folding, and the erosion of these numerous folds has left 

 isolated mountain masses or short ranges in which Cambrian or Primor- 

 dial and other Lower Silurian rocks are exposed. I obtained no fossils 

 that would refer any of the limestones to the Upper Silurian. The gen- 

 eral section already given is based on the system of Dana. 



Cambrian or Primordial. — The best exposure of Cambrian rocks in our 

 district is given in the section eastward from Station 77 (section No. 22). 

 Here we have — 



1. Dark-gray, almost black, quartzites and quartzitic sandstones, with, indu- 



rated argillaceous slates ; iron oxide appears to be characteristic of the 

 lower layers of sandstones ; some of the beds appear to be highly meta- 

 morphosed ; thickness in feet 1, 600 



2. Silvery-gray and steel-gray micaceous slates ; thickness in feet 1, 900 



3. Olive green and gray chloritic slates with fucoidal ? markings, with bands 



of quartzite and indurated clay slates ; thickness in feet 1, 560 



4. Pink and white quartzites, couglomeritic at the top and underlaid by slates 



and limestones ; thickness in feet 2, 000-(- 



Total 7,060+ 



The quartzites here I am inclined to consider as the same series as 

 that given near Station 133 (section No. 21). In the latter place we 

 have between 1,200 and 1,500 feet of quartzites, the lower portion being 

 red and having a general resemblance to those of Station 77 (layer No. 1). 



On Station 130 a similar red quartzite outcrops, but it has limestones 

 just below, and below them a series of very dark green chloritic rocks, 

 unlike those of any other section in our district. I am inclined to place 

 these below the section of Station 77, and consider them of probable 

 Huronian age. I shall include them in the section of the Silurian for 

 the present. None of the sections exposed the underlying crystalline 

 schists. 



The beds given in the sections are probably equivalent to King's 

 Cambrian shales and Cambrian quartzites. No organic remains were 

 obtained from the rocks. Some of the layers appeared to have fucoidal 

 markings, and also what might possibly represent traces of worms. 



Canadian. — The Canadian period is undoubtedly present in our dis- 

 trict as first determined in 1872 by Professor Bradley. 



Above the pink quartzites of Section No. 21 is a series of greenish 

 sandstones and shales with interlaminated limestones and quartzites 

 with a thickness of about 1,300 feet. These beds lie below the lime- 

 stones which contain the fossiliferous layers, and I have provisionally 

 referred them to the Calciferous, confining the Quebec Group to the lime- 

 stones above. The section, although the most complete made by me, 

 does not extend to the top of the group. West of Malade City, the 

 section gives 2,000 feet referred to the Quebec by Bradley. Mr. St. 

 John has kindly furnished me with the following section made at Mount 

 Putnam, beginning at the base : 



a. — Quartzite. 



1). — Dark greenish chloritic slates. 



c, — Heavy deposit of quartzite, dip 85° eastward. 



d. — Soft bluish micaceous shales. 



e. — Heavy deposits of quartzite conglomeritic, in color pink, reddish and white with 

 thin layers of micaceous shales, "dip 80° eastward; locally 20° to 30° east-north- 

 east, and 85° eastward. 



/. — Dark red finely laminated sandstone, thick bed. Potsdam? 



