352 



TRANSACTIONS OF THE CANADIAN INSTITUTE. 



[Vol. V. 



altitudes of from 300 to 400 feet, but these may have been due to a dam 

 near Bog Walk. 



Along the Rio Grande, back of Port Antonio, remains of valley- 

 terraces were noticed at Unity Hall, Golden Vale, and near Windsor, 

 at elevations up to nearly 275 feet ; and along the Foxes, a tributary of 

 the last stream, at 375 feet. Along the coast in this region, there are 

 remnants of baseplanes or terraces at 50-60 feet. On the neck of the 

 ridge connecting the Low Layton volcanic hills with the coast range 

 where the road crosses between two streams, there are the remains of 

 an old terrace at about 375 feet above the sea. At many points west- 

 ward, there is a bench or terrace between 50 and 80 feet, as beyond 

 Buff Bay and Montego Bay. Indeed, there is a fine terrace at the last 

 named place at 50 feet, and several higher benches are engraved upon 

 the point north-east of the bay. Along the northern side of the island, 

 the lower bench of coast limestones commonly rises from 10 to 25 feet. 



South of Montego Bay, along the Grand River, there is a broad 

 valley, which, below Cambridge, has an altitude from 400 to 500 feet 



Figure 8. — A rock island in Great River valley about loo feet high. 



above the sea. Here there are distinct terrace steps, showing the 

 lowering of the base levels of erosion. In another valley, near An- 

 chovy, there are terraces between 675 and '700 feet. Nearer the edge of 

 the mountain region above the Bay of Montego, there are benches at 

 corresponding heights. 



In the valley of Great River, there is a peculiar feature in that there 

 are many islands of rocks rising from 100 to 200 feet above the floor, 

 which is from 400 to 500 feet above the sea. Some of them may be 

 more than half a mile long, but many are shorter and comparatively nar- 

 row, occupying only a few acres. The sides are precipitous as shown in 

 Figure 8. Their surfaces are substantially remnants of a previous floor 

 of the valley (or base level, probably of Layton age), which must have 

 been between 600 and 700 feet above the sea. A thin coating of 



