HILL: GEOLOGY OF JAMAICA. 89 
the Rio Cobre and largely white limestone débris to the west of that 
Stream. 
It has been successively accumulated through several geologic epochs, 
and may ultimately be classified into several distinct terraines. For 
the present, however, we shall recognize but two principal stages, — an 
older one, to which the name of Kingston will be applied, and a newer 
one, which will be called the Montego. 
The Kingston formation is the oldest of the formations of old gravel 
"nd other alluvium occurring upon the plains of the Liguanea type. 
Thig is the formation upon which the city of Kingston and suburbs are 
built, including the strip of land known as the Palisades, and the plain 
extending back of Kingston to the foot of the mountains (seo Plates VI. 
and XIX.). The material consists of boulders, gravel, and pebble of 
Varying sizes, usually very angular, and representing every known 
Material of the Blue Mountain Series. These are embedded ina matrix 
9f dull red arenaceous clay, producing a chocolate soil and derived from 
the Minho beds so conspicuously exposed in situ in the mountains 
North of Kingston. 
The thickness of this formation is unknown, but over 200 feet are 
exposed in the thalweg of Hope River, and probably fully this thickness 
'S concealed. It is even likely that it may be nearly a thousand feet in 
places, 
To the west in St. Catherine the material is similar in composition to 
al the rocks of the mother region drained by the Cobre. Sometimes 
lt grades into a true marine marl, including some white limestone 
Ebris, 
Concerning the origin of this material in St. Andrew, there is no 
doubt but it has been deposited by Hope River, as it debouched from 
the mountains. While most of the material was originally estuarine, 
Some of its upper layers were made by talus fan deposits similar to 
those now seen in the arid region of North America where the moun- 
tain streams debouch upon the desert plains. 
: Asa whole, it represents excessivo deposition, first as estuarine or 
litoral material during an epoch when the coasts were submerged, and 
Mar talus deposits of subsequent epochs, when the land was rapidly 
"sing and stream erosion was very active, as discussed more fully in 
SAU, p. 39, of this paper. The alluvial deposits in the bottom of the 
larger interior basins are also closely synchronous with the Kingston 
f : duh i 
9rmation, and it is probable that these basins are produets of the same 
Breat er 
osion epoch which preceded the Kingston deposition. 
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