PROCHBDrNGS OF GEOLOGICAL SOCIETIES. 
411 
ludc to tlic sea, and caslAviird of the OOth meridian. It includes tlic Scrrani'a 
(as tlic mountainous n;n-ioii is termed) and tlio Llanos or plains to the soulli. 
Tlic most ancient rocks in Venezuela ccmsist ol' mica-schists and gneiss, and 
compose tiie author's "Caribbian Group." 
Tliusc schistose rocks arc highly distorted. In the western portion of the 
district they have a breadth of about thii'ty miles, and rise to the height of 
eight- tlionsand feet. 
Gneiss also is present, and is markedly intcrstratified with the mica-schists. 
The transition is occasionally gi'adual ; but more usually it is sudden and 
abrupt. The gneiss sometimes assumes the irregular structure of granite, but 
is still distinctly bedded. It is occasioiuilly auriferous. Very small propor- 
tions of copper-ores and argeutiferous galena exist in sonic localities. 
The Serram'a also compiises another great group of strata, flanking the 
" Carribbian" rocks on t he south, and in the eastern district rising to a hcigiit 
of more than seven thousand feet, with a breadth of from thirty to forty miles. 
These consist of sandstones, fossiliferous limestones, and shales, and form the 
group provisionally termed " Older Parian." 
These Older Parian strata must be nearly eight thousand feet thick. They 
have been intensely disturbed. Though the fossils can rarely be separated 
from the matrix, yet some were fortunately obtained from near Cumana — 
namely, Trigonm and small Gasteropoda — probably of Lower Cretaceous age. 
These Lower Parian rocks extend westward into New Granada, and are pro- 
bably related to the Neocomian rocks of Bogota. Near their junction with 
the " Caribbian Group" they are often iuterstratified and alternate with rocks 
of igneous origin. 
The Ijlanos are entirely formed of conglomerates and sandstones referable to 
the " Newer Parian Group." In Trinidad a lower and calcareous portion exists. 
Altogether this group probably has a thickness of nearly four thousand feet. 
Possils are abundant in the calcareous division, and seem to represent the 
Lower Pliocene or Upper Miocene series of Eui-ope. 
The upper portion of the Nevi'cr Parian series, which is often shaly, contains 
beds of lignite, frequently admitting of exploitation. The lignite occurs at 
several localities on the mahiland, and also in Southern Trinidad. The ligniti- 
fcrous beds have locally undergone combustion to a great extent, from natural 
causes, such as the decomposition of pyrites. The result is that the strata 
have been indurated and baked for a vertical extent sometimes of seventy or 
eighty feet, the clays assuming various conditions, and presenting the "porcel- 
lanites" and "thermantides" of continental authors. 
The asphalt of Trinidad and the mainland is almost invariably disseminated 
in the upper part of the Newer Parian group. When in situ, it is confined to 
particular strata, which were originally shales containing a certain proportion 
of vegetable debris. The organic matter has undergone a special mineraliza- 
tion, producing a bituminous, in place of the ordinary anthraciferous sub- 
stances. This operation is not attributable to heat, nor of the nature of dis- 
tillation ; but is due to chemical reaction at the ordinary temperature and 
under the normal conditions of the climate. After the solution and removal 
of the bitumen from wood passing into asphalt, the remaining organic structure 
presents peculiar appearances under the microscope. 
The occurrence of asphalt in New Granada and the Valley of the Magda- 
lena in all probability indicates the presence of the Newer Parian strata in 
those districts. 
2. " On the co-existence of Man with certain Extinct Quadrupeds, proved 
by Possil Bones from various Pleistocene Deposits, bearing Incisions made by 
sharp iustrumeiits." By M. E. Lartet, Eor. M.G.S. In a letter to the President. 
The author having for some time past made observations upon fossil bones 
