r 



! 





i!0 





104 G. D. Walcott— Review of Dr. E. W. Ells' s Report 



the Trenton limestone rests unconformably upon tlie Archaean 

 gneiss that forms the bed of the river, at the Falls ; and that a 

 fault has carried the Trenton limestone and superjacent [Jtica 

 shale downward on the east, a short distance northeast of the 

 Falls. The upturned Trenton limestone and Utica shale, form- 

 ing the bluff between the Falls and the St. Lawrence river, 

 contain characteristic Trenton and Utica fossils. For further 

 details the reader is referred to Dr. Ells's report, pp. 22K-25K. 



Cambrian.-^ The rocks which are regarded as constituting 

 the Cambrian system of eastern Quebec are the extension, to 

 the northeast, of those described by Dr. Selwyn, in the reports 

 of the Geological Survey of Canada for 1886 and 1887. They 

 consist for the most part of hard quartzites interstratified with 

 purple, greenish, and black slates. Limited, outcrops of gray- . 

 ish subcrystalline limestone are found occasionally in the town- 

 ships of Mailloux, Buckland and West Broughton. They are 

 associated with black slates and quartzites. Dr. Ells has also 

 referred the trappean rocks of Broughton and Moose moun- 

 tains, also certain associated serpentines, to the Cambrian. 

 North of Chaudiere river, the western boundary of the "Lower 

 Cambrian " is said to be unconformably overlapped by the 

 Sillery red slates, conglomerates, and sandstones, the contact 

 of the two sets of rocks being near the village of St. Claire. 

 It is not improbable that some of the strata referred to the 

 Lower Cambrian by Dr. Ells may prove to belong to that 

 system of rocks ; but in the absence of fossils it is very diffi- 

 cult to say whether the strata under consideration should be 

 referred to the Cambrian or to some pre-Cambrian series of 

 rocks. From the occurrence of Lower Cambrian fossils (Ole- 

 nellus fauna), in grayish limestone, interbedded with purple, 

 green and black slates, in Washington County, N. Y., where 

 the rocks containing them occupy a similar stratigraphic posi- 

 tion to those under consideration, it is not improbable that a 

 similar fauna will be discovered in the Canadian section. Dr. 

 Ells thinks that a part of the strata referred to the older Cam- 

 brian resembles, in many respects, those of the coast series of 

 Nova Scotia, while in part they resemble the lower portion of 

 the Cambrian of New Brunswick. Stratigraphically they oc- 

 cupy a position between the chloritic and micaceous schists of 

 the Archaean and the superjacent strata of the Sillery '{page 

 87K). (See First Report, pp. 23J-29J, for an excellent 

 description of the character of the rocks referred to the 

 Cambrian.) 



The Cambrian strata of the Sillery terrane will be noticed 

 under the description of the " Quebec Group." 



Quebec Group. — An excellent historical review is given of 

 the literature pertaining to the " Quebec Group," from the 



