an Geology of Portion qf Prowiim of Quebec. 103 



to this system, found south of the St. Lawrence river, range 

 from the Hudson, downward, to the Cambrian. The region 



in which they occur is divided into an eastern and western 

 area ; the former including the rocks that occur between the 



central Arclnean anticlinal, or the northward extension of the 

 Green mountains, and the United States boundary, and the lat- 



. the strata situated between the Archaean anticlinal and the 

 St. Lawrence river. The eastern area is the prolongation to 

 the northeast of the great area of Cambro- Silurian rocks, which 

 lies between the Stoke Mountain range and the Cambrian rocks 

 of Lake Biegantic and vicinity/- They consist largely of dark 

 gray and blackish, sometim 66 plumbaginous slates, with grayish 

 sandstones ; the former sometimes ochre-spotted and display- 

 ing, on weathered surfaces, a characteristic striped or banded 

 aspect. Calcareous rocks are, as a rule, absent, although they 

 have been seen on the upper Chaudiere river. 



The western area of the Cambro-Silurian rocks, or those in 

 the vicinity of the St. Lawrence river, present, at several 

 places, many features differing from those of the eastern area. 

 Dr. Ells considers that the formations are, for the most part, 

 presumably of a later age, as indicated by the fossils. At St. 

 Nicholas, fourteen miles above Levis, the contact between the 

 shales and sandstones of the Hudson, and the red, green, and 

 black shales of the Cambrian Sillery terrane is shown on the 

 river beach, near the cliff. The Hudson sandstones contain 

 graptolites and mollusks characteristic of that zone. 



The Utica-Trenton ontcrop extends nearly three miles and a 

 half, where it is cut off by a line of fault. At Pointe an Pla- 

 ton highly bituminous, brownish gray shales represent the only 

 typical Utica rocks seen on the south side of the river, in this 

 direction The Levis rocks, occurring about Levis, will be 

 spoken of in describing the " Quebec Group." 



The strata on the north shore of the St. Lawrence have 

 already been described in the Geology of Canada, 1868. Dr. 

 Ells has added many details and, also, given lists of the fossils 

 occurring in the Trenton, Utica and Hudson terranes. 



Dr. Ells made a careful study of the rocks of the Montmor- 

 enci Falls, eight miles below Quebec. He decides, from the 

 evidence of the fossils and from the character of the sediments 

 that the conclusions stated by Sir William Logan, in 1863 

 (Geology of Canada), as to the structure at this place, and sub- 

 sequently, by Dr. Selwyn, in sundry papers, are clearly main- 

 tained. In company with Drs. Selwyn and Ells I carefully 

 studied the geology of Montmorenci Falls and vicinity, in 

 August, 1889, and 1 fully concur with them in the view that 



* See First Report, 14J-23J. 

 Am. Jour. Sci.— Third Series, Vol. XXXIX, No. 230.— Feb., 1890. 

 8 



