SOMK LOCAL DETAILS. 175 



formation of tliis county tliere is a very thick bed of 

 conglomerate, the outcrop of which, owirig to its compara- 

 live hardness and great mass, forms a high ridge extending 

 from the hill behind Xew (llasgow across tiie Kast and 

 Middle rivers, and abaig the south of the West river, and 

 then, crossing the West river, re-appears in Rogers' hill. 

 The valleys of these three rivers have been cut tlirough 

 this bed, and the material thus removed has l)een heaped 

 u[) in hillocks and l)eds of gravel, along the banks of the 

 .-streams, on the side toward which the water now Hows, 

 which happens to be the north and north-east. Accord- 

 ingly, along the couise of the All»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 boulder- 

 clay, showing that the cutting of these valleys was 

 completed after the drift was produced. Sinnlar instances 

 of the connection of gravel with conglomerate occur near 

 Antigonish, and on the siiles of the Cobecjuid mountains, 

 where some of the valleys have at their southern entrances 

 immense tongues of gravel extending out into the plain, 

 as if currents of enormous volume had swept through 

 them from north to south. 



The stratified gravels do not, like the older drift, form a 

 continuous sheet spreading over the surface. They occur 

 in mounds and long ridges, or eskers, sometimes extending 

 for miles over the country. One of the most remarkable 

 of these ridges is the " Boar's Back," which runs along the 

 west side of the Hebert river in Cumberland. It is a 

 narrow ridge, perhaps from ten to twenty feet in height, 

 and cut across in several places by the channels of small 

 l»rooks. The ground on either side appears low and Hat. 

 For eight miles it forms a natural road, rough, indeed, but 



