8. F. Pechham—The Pitch Lake of Trinidad. 453 



to verify my first impression upon a second visit, as it proved con- 

 clusively that, notwithstanding the vast quantities of pitch that had 

 been removed from the lake, there is still a movement out of the 

 lake, glacier-like, down the slope to the sea. 



My first impression as I looked over the expanse of the lake was 

 a surprise. I had expected a scene of desolation. Nothing could be 

 further from the reality. In the centre were the islets so often 

 described. Within and around them a dark area resembled the 

 muddy bottom of a pond from which the water liad been drawn 

 off", with here and there patches and intervening streams of water 

 remaining. From the border of this dark centre, the vegetation arose 

 higher and higher around almost the entire circumference of the 

 lake, until it reached a border of palm trees from thirty to fifty 

 feet high. As I looked over the lake 1 beheld on a vast scale 

 the appearance of asphalt beds that I had man}"^ times seen in 

 California. 



An examination of the borders of the lake showed that it occupied 

 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 north- 

 east 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 inside 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 asj)halt 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 frequently in that direction 

 to a considerable amount, notwithstanding numerous artificial drains 

 lead out of the circumference of the lake and the wide natural outlet 

 down the slope to the sea. To the north-west towards the sea, 

 a heavy stream of asphalt has overflowed to the sea, forming 

 a barrier reef for a considerable distance. Asphalt has also over- 

 flowed 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 present 

 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 

 volcano, 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 



