204 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 24, 



these localities, both to the east and west of the foot-prints, are in- 

 cluded in the line of section given with last year's communication*. 



Another of the track-bed localities is in the vicinity of Point 

 Cavagnol, on the south side of the Lake of the Two Mountains, about 

 fifteen miles from the locality near the mouth of the Beauharnois 

 Canal. Both of these localities are on the western side of the axis 

 of the flat anticlinal arch, formed by the projecting tongue of sand- 

 stone between Beauharnois and Mont Calvaire, as described in my 

 former paper. To the westward of the tracks of Point Cavagnol the 

 country is so covered with drift and forest, that no traverse, starting 

 immediately from the bed, has been attempted in that direction 

 beyond a few miles, in which no exposure was met with ; but on the 

 lake side of the tracks, and a short distance beneath them, a bed of 

 red sandstone occurs. 



The fourth new locality is on one of the islands of St. Genevieve, 

 between two and three miles east of St. Ann, at the upper end of the 

 Island of Montreal. This spot is about seven miles from the Beau- 

 harnois village exposures, and, with them, is on the east side of the 

 anticlinal axis. If a line be followed obliquely across the anticlinal 

 from the Canal track-bed to that of St. Genevieve Island, and pursued 

 to the White Horse Rapids between the Islands of Montreal and 

 Jesus, a little below Isle Bizard, coarser sandstones would come from 

 beneath the Canal track-bed about a mile out in Lake St. Louis 

 (see fig. 2, & Section 2 of the Map). They are represented by the 

 sandstones and conglomerates of Cascade Point and Cascade Island 

 close by, of which they would be in the strike. A thickness of 65 feet 

 of these coarser strata can be made out at the Point, and they are 

 probably as much below the track-bed. The traverse-line would cross 

 Isle Perrot, which is all underlaid by the sandstone, and on reaching 

 the track-bed of St. Genevieve Island, not a mile on the north side 

 of Perrot, we again find the rock marked by Scolithus, with which 

 it is in some spots completely honeycombed to the depth of 3 feet, 

 while it is also interstratified with thin irregular calciferous bands. 

 St, iVnn's Point may be considered in the strike of the St. Genevieve 

 Island, and here we still find the sandstone marked by Scolithus ; 

 while on Isle Perrot, opposite, there occurs a bed of red sandstone 

 identical in character with that of Point Cavagnol, and angular frag- 

 ments of the same strew the shore above St. Ann. Proceeding 

 northwards, we find immediately behind the village of St. Ann's 

 the outcrop of the Calciferous Sand-rock holding geodes of calc-spar ; 

 and in a quarry to which resort has been had for building-stone we 

 meet with a Murchisonia, like M. gracilis, but flat in the whorls, a 

 Pleurotomaria, like P. suhconica, but more depressed, Leperditia 

 Anna (Jones, MS.), and Orthoceras. Further on the road, about 

 half a mile, a Raphisto^na occurs in calcareo-arenaceous beds, which 

 with thin geodes of calc-spar are met with in several places farther 

 on. We then, in a low escarpment, come upon a rock composed 

 almost entirely of Atrypa plena, a species characteristic of the Chazy 

 Limestone. The rock usually afl'ords good building-stone as well as 

 * Loc. cit. p. 249, and repeated here (fig. 1 & Section 1. of the Map). 



