148 INDEX TO THE STRATIGRAPHY OF NORTH AMERICA. 



L-Q 10-21. CANADIAN SHIELD. 



Throughout the region covered by the Canadian Survey there occur areas of 

 unfossihferous clastic, usually sandy formations (the Athabaska-Nastopoka series), 

 which rest unconformably on the metamorphosed or disturbed pre-Cambrian rocks 

 and are themselves but httle disturbed. They have been described as " Cambrian" 

 by the Canadian Survey, but are now believed to be older than the Olenellus fauna, 

 and consequently to belong to the late pre-Cambrian, according to the classification 

 in this paper. i ^ 



M 19-20. GASPE PENINSULA. 



The Cambrian ("Quebec group") is poorly exposed on the Gaspe Peninsula 

 but is described by Logan ^'^^ as follows : 



Below the Magdalen, the breadth of the formation has been ascertained by transverse sec- 

 tions in two places only; one of them being at the Great Pond River, where it is about 2 miles, 

 and the other at Griffin Cove, where it is less. Approaching Cape Rosier the breadth gradually 

 diminishes; and the Hudson River strata finally disappear under the waters of the Gulf, at 

 Anse a la Tierce. The remainder of the distance to Cape Rosier is occupied by the gray 

 calcareous sandstones, red shales, and limestone conglomerates of the Quebec group. 



In the Great Pond section also the rocks which succeed to the Hudson River strata belong 

 to the Quebec group, and they prevail for a breadth of about 1 1 miles, before becoming covered 

 up by the Upper Silurian limestones. Two miles in the middle of this section are occupied by 

 sandstones of the Sillery series, with the red shales which usually accompany them. The dips 

 on both sides of the area occupied by these sandstones are to the southward; the inclination 

 on the north side being 51° and that on the south side 64°. It is probable, however, that the 

 strata are arranged in a synclinal form, and that those on the south side are inverted ; the gen- 

 eral synclinal probably contains several subordinate undulations of a similar character. The 

 rocks on each side of the sandstone appear to belong to the Levis formation; some of the naasses 

 on the south side resemble the magnesian conglomerate bands of Poin^ Levis. * * * • 



On the section from Griffin Cove, at the distance of 2 miles 'south westward from the coast, 

 about one-eighth of a mile is covered with large angular fragments of greenish sandstone, some 

 of which are fine conglomerates, with quartz pebbles as large as peas. None of this rock has 

 been seen in place; but the abundance and angularity of the fragments leave little doubt that 

 the beds can not be far removed. The position of the fragments may therefore be assumed as 

 that of the Sillery sandstones, particularly as they occur in what would be a continuation of the 

 axis of the Sillery synclinal on the Great Pond section. Between the position of these sand- 

 stones and the Hudson River strata on the coast there would be room for the rocks of the Levis 

 formation, but none of them have been there observed. * * * 



Between Cape Rosier and the base of the Gaspe Hmestones a sudden turn in the coast gives 

 a natural section, nearly at right angles to the strike, of 2i miles in length. The coast is low 

 and shelving, and the violence of southeastern storms has heaped upon it a great mass of gray 

 limestone shingle, which covers nearly the whole of it, with the exception of three points. One 

 of these is Cape Rosier itself, where a breadth of 450 yards of the strata, including what are 

 seen between high and low water marks, is exposed. The strata consist of gray limestones, in 

 beds varying from 6 inches to a foot in thickness, with two thicker conglomerate beds, made up 

 of gray limestone pebbles in a calcareous matrix, very much resembling the conglomerates of 

 Ste. Anne des Monts, the whole interstratified with black and gray shales. Separated from the 

 strata of the cape by an interval of 1,000 yards, covered by limestone shingle, there occur, at 

 the next point exposed, gray, yellow-weathering hmestones, probably magnesian, interstrati- 

 fied with jet-black and gray shales, with a band of conglomerate or brecciated limestone on 

 the northeast side. The distance across the strata is about 800 yards; but there are intervals 

 of concealment in it, making up 300 yards of the amount, and, though the dip is pretty uniform 

 in direction to the southwest, there are variations in the inchnation, which ranges from 44° to 

 60°. Another interval of concealment occurs, of about 1,000 yards across the measures; but a 



