62 Till': i< I*: A(jk in Canada. 



tlmt of ice. I tun hujt that this is the cnso with iiniiiy of 

 the iinlcutiitinDs of the ('oust of Novii Scotiii, which iiro 

 (Mit iiilo the softer and iiioic shattcriMl liaiids of rock, 

 and show, in raised hcachcs and ;,'iav(d ridges like those 

 of the ])iesent coast, the levt.'ls of the sea at the tiine of 

 theii' formation." 



To the period df tlie honhler-clay wc may icfei' lliose 

 ridj^cs and |ia\('mcnls of hiadders indti^hh-d in this clay 

 oi' coMliiiuons with it, and which tcslifv to the earrvinj' 

 and jtackin^f power of ice. WC shall Ihid, howcNci', that 

 such moraine-like ridj^cs are not contiiicil to this period, 

 hul occur alonj,' the si'a-mar^dns of the Later Pleistocene, 

 and are e\'en at this day in process of formation on a 

 considerahle scale alonjn' the borders of the St. Lawrence. 



2.-77,,. Lain Clnji. 



This dejiusit constitutes the sultsoil o\er a lar^c portion 

 of the j,'reat plain of Lower Canada, varying' in thickness 

 from a few feet to HO or perhaps even 100 feet, and 

 us\ially ri'stin,^' on the lioulder-clay, into which it some- 

 times a])pears to ^lailnato, the material of the Leda clay 

 hcMUif of the same natuii; with the finer portion of the 

 paste of the houlder-clay. Its nanu; is derived from the 

 l)re.sence in it of shells of LalK i/hirla/ls, often to the 

 exclusion of other fossils, and usually in a perfect state, 

 with both valves united. 



The ty[iical Leda clay in its recent slate is usually ^ray 

 in colour, unctuous, and slightly calcareous. Some beds, 

 however, are of a reddish hue; and in thick sections 

 recently cut, it can be seen to j)resenl layers of dil'l'erenl 

 shades and occasional thin sandy bands, as well as layers 

 studded with small stones. It sometimes holds hard 

 calcareous concretions, which, as at Green's creek on the 



