176 Tertiary. 



coals, or more imperfeci varieties of bituminous coal. It contains many 

 small roots and branches, apparently of coniferous trees allied to the 

 spruces. The vegetable matter composing this bed, must have 

 flourished before the drift was spread over the province, so that it be- 

 longs to some part of the great Tertiary group of rocks, of which the 

 drift is the latest member. 



Dr. Dawson accounted for the drift phenomena of Nova Scotia, in 

 this manner. Let us suppose the surface of the province, while its 

 projecting rocks were uncovered by surface deposits, exposed for many 

 successive centuries to the action of alternate frosts and thaws — the 

 whole of the untraveled drift might have been accumulated on its 

 surface. Let it then be slowl3^ submerged, until its hill-tops should 

 become islands or reefs of rocks in a sea loaded in winter and spring 

 with drift ice, floated along by currents, which, like the present Arctic 

 current, would set from N. E. to S. W., with various modifications 

 produced by local causes. We have, in these causes, ample means for 

 accounting for the whole of tlie appearances, including the traveled 

 blocks and the scratched and polished rock surfaces. 



'The. stratified sand and gravel rests upon and is newer than the un- 

 stratified drift. This may often be seen in coast sections or river 

 banks, and occasionally in road-cuttings. In Pictou county there oc- 

 curs a very thick bed of conglomerate, of the age of the Coal 

 Measures, the outcrop of which, owing to its comparative hardness 

 and great mass, forms a high ridge extending from the hill behind New 

 Glasgow, across the East and Middle rivers, and along the south side 

 of the West river, and then crossing the West river reappears in Rogers 

 Hill. The A^alleys of these three rivers have been cut through this bed, 

 and the material thus removed has been heaped up in hillocks and beds 

 of gravel, along the sides of the streams, on the side toward which the 

 water now flows, which happens to be the north and northeast. Accord- 

 ingl}', along the course of the AU)ion Mines railway, and the lower parts 

 of the Middle and West rivers, these gravel beds are everywhere exposed 

 in the road-cuttings, and may in some places be seen to rest on the 

 bowlder-clay, showing that the cutting of these valleys was completed 

 after the drift was produced. The stratified gravels do not, like the 

 older drift, form a continuous sheet spreading over the surface. They 

 occur in mounds, and long ridges, sometimes extending for miles over 

 the country. They are supposed to have been distributed when the 

 country was being elevated, while the bowlder drift was deposited 

 when the land was subsiding beneath the sea. 



T. A. Conrad separated the Eocene of Mississippi and Alabama, in 



