Crosby. | 50 [October 2, 
part of the continental margin, we have evidence that the subsi. 
dence producing the Dragon’s Mouth was general, not local. Far- 
ther west, in the State of Barcelona, there is another well-marked 
break in the littoral cordillera, and an examination of the maps seems 
to show that the en echelon plan characterizes this entire mountain 
system. 
The rocks composing the Northern Mountains of Trinidad and 
the major part of the Parian range, were designated collectively as 
the “ Caribbean Group” by Wall and Sawkins, in their Report on 
the Geology of Trinidad, published some twenty years since. ‘These 
mountains are monoclinal. The strata almost everywhere exhibit 
southerly dips of thirty to sixty, or even more, degrees, and the beds 
to the north are presumably the oldest. The prevailing southerly 
dip is well expressed in the topography, the northern face of the 
mountains where the strata are broken approximately at right angles 
being very abrupt, with an average length of perhaps two miles; 
while the opposite slope, substantially parallel with the bedding, is 
two to four times as long, and correspondingly gentle. The ranges 
are cut transversely by numerous lateral valleys, which are for the 
most part deep and narrow, natural sections, frequently laying bare 
the very heart of the mountains. Some of these, at least, appear to 
have originated in transverse faults, the cliff giving rise to the re- 
markable waterfall of Maracas (three hundred and forty feet high) 
certainly demanding such an explanation for the valley of which it 
forms one wall. Notwithstanding the diversified and sharp-featured 
topography of these mountains, the geological explorer is much ham- 
pered by the paucity of rock outcrops; for sub-aerial decomposition 
goes on very rapidly under the influence of tropic rain! and heat; 
and, besides, such exposures as exist are usually practically inacces- 
sible, on account of the tangled mass of vegetation that overruns 
every rood of uncultivated ground. 
Mr. Guppy, in a recent paper? on the *“ Caribbean Group,” says:— 
‘¢ These rocks attain collectively a thickness of more than ten thou- 
sand feet. The whole thickness of the group is probably much 
greater than this; for the evidence furnished by dip and other cir- 
cumstances leads to the inference that a portion of the series, as 
1 Trinidad enjoys an annual rainfall ranging from 56 to 91 inches, with an aver- 
age of about 80 inches. 
2 Proc. Sci. Assoc. Trinidad, 1, 104. 
