454 >S'. F. Pecliham — The Pitch Lake of Trinidad. 



with or resembling those described by Mr. Guppy.^ Into this 

 ascending current, resembling a quicksand, was projected bitumen, 

 at intervals in very large amounts, so that irruptions of mud have 

 coincided with and alternated with irruptions of bitumen, the whole 

 building up the cone and at times overflowing it, while the basin 

 has gradually filled with bitumen to the exclusion of mud. 



It is, however, equally evident that for an indefinite period there 

 has been an outflow of bitumen from the crater towards the sea, 

 at La Brea, not over its rim, but through a crevice in its side — in. 

 fact, through its broken-down side ; and that, notwithstanding the 

 vast quantities of asphalt now being taken from the lake by the 

 Concessionaires, the movement is still out of the lake. 



Capt. Alexander, in 1832, spoke of the flow out of the lake 

 as "immense.'' Manross, in 1855, says, "this stream of pitch has 

 been dug through in several places, averaging from 15 to 18 feet 

 in depth." A well dug at one point on the slope of the overflow 

 was abandoned still in asphalt, at the depth of forty feet. Several 

 village lots have been excavated to a depth of twenty feet, still 

 in asphalt. The invariable reply of the negroes to the question, 

 "Have you ever dug through the asphalt?" was, "No, sir." The 

 conclusion that I reached on the ground is, that the asphalt flowing 

 down the slope to the sea fills a ravine excavated by water, and that 

 it is slowly moving out of the lake with the pressure of the asphalt 

 in the lake behind it. This conclusion is in harmony with the 

 testimony of all the observers above quoted for the last hundred 

 years. 



Concerning the condition and appearance of the pitch within 

 the lake, I think it is quite certain from all the observations above 

 quoted that the pitch has gradually become harder and more stable 

 during the last 106 years. I do not think that later observers have 

 any right to question the veracity of those who have preceded them. 

 Dr. Nugent says that in 1807 the centre was so soft that it could be 

 dipped up with a cup. Alexander describes it in 1832 as so unstable 

 that the weight of a man produced a bowl-like depression to the 

 depth of one's shoulders, and that the heat gradually increases as one 

 walks ofi' towards the middle with his shoes off. Manross, 23 years 

 later, says, " It may be that the material has become much harder 

 since the first accounts of it were written ; but it is difficult to 

 understand how the weight of a man can have displaced a mass 

 of pitch equal to a 'great bowl' as deep as the shoulders." Kingsley, 

 24 years later, is practically of the same opinion. At the time of my 

 visit, a man was loading a cart near the centre of the lake, and while 

 they did not remain in one place long enough to secure a lai'ge load, 

 there was no apparent danger of their being engulfed. 



^ Guppy says (Quart. Journ. 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." 



