on Geology <>/' Portion of Proving of Quebec. L09 



the correctness of the viewa advanced by Dr. Selwyn and lias 

 also added materially to our own knowledge of the geologic 

 Btrnctnre and Btratigraphic succession of the beds forming the 

 unaltered series of the "Quebec Group." IK' has shown that 



the order of succession of the strata was inverted by Logan, 

 and that the Levis .-cries is conformably superjacent to the 

 Opper Sillery (Lanzon of Logan), and that the Lower Sillery 



forms the base ^f the section in the vicinity of Quebec. 



The study of the relations of the Levis to the Sillery, at 

 Levis, is a beautiful piece i>( Btratigraphic geology and a most 

 careful and conscientious work. I accompanied Dr. Ells over 

 the area, in August, 1889, and fully concurred with him in his 

 views of the structure The surface outcrops are essentially 

 ae mapped by Sir Wm. E. Logan, in 1863. The radical 

 difference between the interpretation of the latter and Dr. Ells 

 is that Dr. Ells places the red Sillery strata below the Levis 

 and not above, as was done by Logan. Dr. Ells recognizes 

 four anticlinal axes, two of which, at least, are completely 

 overturned. One of these is so well shown that I obtained a 

 very good photograph of it, on the road leading up the cliff, 

 300 yards south of the lower ferry at Levis. Beneath the 

 Levis strata the red shales of the Sillery are shown, and the 

 synclinals of Levis strata rest in the red shales of the Sillery. 

 The tracing of the anticlinals and synclinals was by means of 

 the stratification and the occurrence of the sub-faunas in the 

 graptolitic shales of the Levis terrane. On the eastern margin 

 of the Levis beds an overturned synclinal has placed the red 

 shales of the Upper Sillery upon the graptolitic shales of the 

 Levis. In the upper beds of the Sillery a few graptolites and 

 brachiopods indicate the intimate paleontologic relations of 

 the upper portion of the red Sillery shales with the dark grap- 

 tolitic shales of the Levis terrane. A list of the graptolites 

 at each locality is given by Dr. Ells, with a discussion of the 

 Btratigraphic relations of the several fossiliferous zones. 



The strata of the city of Quebec were referred to the Levis 

 series by Logan and to the pre-Potsdatn Taconic by Jules 

 Maroon. Dv. Ells gives a list of forty species of fossils, 

 obtained from the shales and interbedded dark limestone, that 

 were collected by Messrs. Giroux and Ami, and determined by 

 Mr. II. M. Ami. The fauna is essentially Middle Ordovician 

 or Trenton-Utica, and proves conclusively that the Quebec 

 city strata are neither Levis, nor pre-Potsdam. Prof. Lap worth 

 thinks that the graptolites indicate the Lower Trenton, and 

 Mr. Ami considers the Montieulvporoide to be of Lower Tren- 

 ton age. 



The limestone conglomerates of the "Quebec Group" have 

 been a fruitful source of confusion since they were described 



