1853.] BIGSBY — GEOLOGY OF QUEBEC. 95 



by shale. From the middle of Sillery Cove to Dr. Mills' Quarries 

 (1:^ mile westwards) brown and red shale alternate with sandstone, 

 the dip being S. or S.S.E., at an angle often of only 15°. 



In these quarries the sandstone, as usual, has a greenish matrix, 

 with quartz pebbles as large as duck-shot, small flakes of plumbago, 

 and silvery mica, and also with many fragments of shells {Or this 1). 

 These shells were first noticed many years ago by Dr. Lyons, Surgeon 

 to the Forces. 



Beyond Dr. Mills' Quarries up to a nameless point three-quarters 

 of a mile beyond, and at the narrowest part of the St. Lawrence for 

 many miles up or down, the sandstone is black, and in hard thick 

 strata interleaved with clay-shale in nearly equal quantities, the dip 

 being high and S.S.E. ; and still more easterly, it occurs in bold and 

 extensive flexures which the nature of the ground will not allow of 

 being traced out. 



The little capes or points of land are generally of sandstone, this 

 rock being less liable to destruction than the shale. 



These two rocks now continue along shore in numerous intercala- 

 tions of various breadths up to Cap Rouge ; the red shale slowly 

 gaining possession of nearly the whole surface of the slope, its strike 

 (N.E, and N.N.E.) being parallel to the shore-line (see Map). From 

 about half a mile westward of the Point at the narrows to Cap 

 Rouge we see, with surprise, in the cliffs about and above high-water- 

 mark, many angular blocks of dark limestone, of the sandstone of the 

 place, and rounded boulders of gneiss, imbedded in the surface of 

 the clay-shale. They have been raised and driven into it by the ice 

 of spring freshets, — and this with immense force, because these 

 boulders are commonly very large. The visible part of one of these 

 buried masses of gneiss is 5 feet across. The uncovered end of one 

 mass of sandstone thus thrust into the cliff is 3 feet long by 2\ feet 

 broad ; it has displaced all the shale edgevdse for three or four feet 

 around. These blocks are generally solitary, but not always. 



From Cap Rouge, the north shore of the St. Lawrence westwards 

 to near the church of St. Augustine (4^ miles) is so covered by allu- 

 vium that little fixed rock, except occasionally shale, is seen ; and 

 we are carried out of the district that forms the subject of these 

 pages. 



South of the St. Lawrence from Point Levi to St. Henry. — 

 Crossing now to the south side of the St. Lawrence we everywhere 

 find the country based on the same minute alternations of clay-slate, 

 coarse sandstone, calcareous and other conglomerates, that we met 

 with on the north side of the river. The stratification is much more 

 steadily to the N.E., with a south-east dip, — so varying by slow de- 

 flection as to give a waved appearance to the whole ; remarkable 

 contortions, however, will be pointed out in the proper place. 



We will first traverse the country for ten miles S.S.W. to the vil- 

 lage of St. Henry, crossing the strike, and then notice some of the 

 larger rock-exposures in the cliffs about Point Levi, and for some 

 miles along the River St. Lawrence east and west of that point. 



VOL. IX. — PART I. H 



