34° TRANSACTIONS OF THE CANADIAN INSTITUTE. [VOL. V. 



enters a broad valley excavated out of the mountain mass of the White 

 Limestones. At various altitudes up to 150 feet above the sea, there 

 are horizontal beds of water-worn gravels, resting upon the surfaces of 

 the White Limestone. The pebbles are more or less composed of the 

 White Limestones, and in size usually less than four inches long. While 

 these gravels occur up to an elevation of 50 feet or more above the 

 floor of the valley, they are only fragmentary remains of a deposit which 

 probably filled the valley. Above the gravels there are some marls, 

 which appear to be higher beds of the same series, as it is characteristic 

 of this formation and its equivalents in Cuba that the lower beds are 

 apt to contain the greater quantity of pebbles, and the same is true of 

 the equivalent loam and gravel series. 



On the road between the mouth of the Hope River and Kingston, at 

 the end of Long Mountain, where it almost projects into the Caribbean 

 Sea, there is a conglomerate loosely held together, composed of mostly 

 subangular gravel of White Limestone derived from the adjacent moun- 

 tain. The bed dips at 10 degrees towards the sea, and rises to an 

 elevation of 150 feet, overlying the surface of which there is an uncon- 

 formable bed of sand and gravel. This conglomerate is a fine exposure 

 of the mechanical character of the Layton formation, which is also here 

 succeeded by a newer formation. It further indicates the more recent 

 elevation of the mountains. Between the mouth of the Hope River 

 and this point, along the roadside, there are several exposures of gravel 

 and loam of which the pebbles are sometimes one or two feet long, 

 covered by blocks of the White Limestone, occasionally four feet long, 

 which are cemented into a bed four or six feet thick. All of these 

 gravels and loams are quite unlike the upper deposits which will form 

 a distinct topic. Some of the older alluvium described by the Jamaican 

 geologists belong to this horizon ; but the relationship of the latter 

 divisions of the geological scale were not considered by them. 



Crossing the island again, to Montego Bay and going westward to 

 Lucea Bay, the post- Miocene formations may again be seen near the 

 coast. At Hopewell, a kw miles west of Montego Bay, occupying an 

 embayment in the White Limestones there is a marl containing modern 

 fossils, upon whose eroded surface rest some gravel deposits, which are 

 surmounted by the modern limestone of the region. The lower marls 

 are thought to have the same position as the Layton series farther 

 east. At twenty and a-half miles west of Montego Bay, apparently 

 the same beds recur, but as there are no overlying deposits resting upon 

 them, there is always the danger of mistaking them for the more 

 modern limestones of the coast, as the fossils have no determinative 



