1879.] Native Bitumens and the Pitch Lake of Trinidad. 239 
range of mountains, a detached link of the great littoral Cordillera 
of Venezuela. These are composed of ancient crystalline strata, 
and stand like a wall between the Tertiary plain on the south and 
the Caribbean sea, and the long chain of volcanic islands on the 
north. There is scarcely a trace of true volcanic action observa- 
ble in Trinidad, the hot mud springs—the so-called mud volcanoes 
—hardly coming in that category. They may be classed as 
hydro-thermal but not as igneous phenomena. I have also seen 
little or no evidence of volcanic action during the past epochs in 
the history of the island; and the frequent severe earthquake 
shocks of the regions on the west and north are very rarely felt 
with destructive force in this favored isle. 
Asphaltum, usually accompanied by mineral tar and petroleum, 
occurs at many points on Trinidad and also on the adjacent main. 
But the largest and most interesting deposit, not only of this 
region but of the world, is that known as the Pitch Lake. This 
is on Point La Brea (La Brea being Spanish for the pitch), in the 
south-western part of the island, and one mile from the Gulf of 
Paria. The topography of the country about the lake is ex- 
tremely simple; from three sides—north, west and south—-the 
land slopes gradually upward from the sea to the surface of the 
lake, which lies one hundred and thirty-eight feet above the gulf; 
while on the east the land is slightly higher than the lake. In 
other words, the Pitch Lake is on the faintly-marked shoulder of 
a broad, low ridge which, projecting into the gulf of Paria, forms 
the peninsula or promontory of La Brea. Contrary to all topo- 
graphic laws and precedents, this so-called lake is not in a valley, 
but on a hill-top. I have already denied the existence, both past 
and present, of volcanic phenomena in this region, and yet the 
situation of this remarkable deposit of asphalt is very much as if 
the broad-mouthed crater of a low-lying volcano were filled to 
the brim with this material. I say filled to the brim, because on 
the three sides named above, the surface of the pitch is even with 
the brow of the hill, and more so, for at many points the viscous 
substance is constantly overflowing and moving seaward, after the | 
manner of very sluggish lava streams. The motion is extremely 
slow, the pitch, where it issues from the lake, being a brittle solid. 
The moving masses present curved lines and surfaces, which are 
convex downwards; and Kingsley has very aptly likened these 
Streams of asphalt to glaciers, the lake representing a mer de 
