S. H. Peckham—Pitch Lake of Trinidad. 45 
border of palm trees from thirty to fifty feet high. As I 
looked over the lake I beheld on a vast scale the appearance of 
asphalt beds that I had many times seen in California. 
An examination of the borders of the lake showed that it 
-oceupied a bowl-like depression in a truncated cone that rested 
against the side of a hill that rises above the lake to the south- 
west. Along the line of ascent that I had followed, the slope 
towards the northeast to the sea is very gradual. In other 
directions the ascent is abrupt, sometimes steep, especially 
toward the south. These slopes are covered with tropical 
jungles consisting of palms of various species, sedges, canna and 
wild vines. The border of this depression presents upon the in- 
side for the most part an escarpment of sand and clay, that has 
evidently been built up and afterwards broken down in many 
places by water. Wherever excavations have been made in 
the cone or the escarpment they show that the cone consists of 
both asphalt and earth. At a point on the south side, near 
where the road leaves the lake, the appearance of the surface 
indicates that the drainage of water from the lake was fre- 
quently in that direction to a considerable amount, notwith- 
standing numerous artificial drains lead out of the circumfer- 
ence of the lake and the wide natural outlet down the slope to 
the sea. To the northwest towards the sea, a heavy stream of 
asphalt has overflowed to the sea, forming a barrier reef for a 
considerable distance. Asphalt has also overflowed to the 
south, and the general appearance of the escarpment seemed 
to indicate that at some remote period the basin now occupied 
by the lake had been filled some three feet higher than the 
Ypresent level of the lake. I looked in vain for any evidence 
that the mass within the lake had been recently depleted; but 
I am aware that observations at considerable intervals of time 
would be necessary to establish that fact, by referring the 
mean level of the lake to some fixed point by means of a very 
careful trigonometrical survey. 
A very careful study of the present appearance of the lake 
and its boundaries led me to believe that the suggestion of Mr. 
Richardson, that the lake occupies the crater of an old mud 
voleano, is correct, and that it has been built up of very 
unstable material, through contact of water issuing in large 
quantity from subterranean springs which has come in contact 
with strata identical with or resembling those described 
by Mr. Guppy.* Into this ascending current, resembling 
* Guppy says, (Quar. Jour. Geol. Soc., xlviii, 527, note) ‘“ When a piece of the 
foraminiferal rock is placed in water, it absorbs it rapidly and falls asunder, and 
the water which enters into union with it is given up only to evaporation. .. . 
From these properties it follows that the natural soil roads passing over these 
rocks become in the wet season the worst quagmires it is possible to imagine.” 
Of another bed, “In the presence of water this rock is the most incoherent of 
any I have ever met with. ... It falls into powder at the mere contact of 
water.” 
