THE PITCH LAKE OF LA BREA. 325 



acres, and its appearance is that of a dull, still, dark waste atra 

 regna. It is irregularly circular and its surface perceptibly convex, 

 being more elevated in the centre, and thence insensibly declining 

 on all sides. In the centre also the bitumen is quite soft, in fact, 

 semi-liquid ; but it becomes more and more hardened as it ap- 

 proaches the circumference. Excepting the soft central parts, 

 the surface is intersected in all directions by numerous fissures 

 or chasms, varying in breadth from two to sixteen feet, and from 

 half-a-foot to seven feet in depth, widening also at the surface and 

 terminating acutely at the bottom ; thus producing, as it were, 

 inverted angular hollows, while the sides are regularly rounded. 

 These crevices are, at all times, filled with fresh water. Here 

 and there, where the bitumen is mixed with earthy matters, grow 

 lichens and mosses with a few coarse grasses, whilst stunted icacos, 

 sour-sop trees, &c., and caratas, form insulated clusters oases, in 

 a manner surrounded on all sides by water. 



The centre of the lake the pitch-pot, or cliaudiere, as it is 

 called is, at all times, so soft that it would be impossible to 

 venture on it without incurring the danger of being engulfed ; 

 there a slow and constant bubbling and puffing is perceptible, 

 accompanied by emissions of gaseous substances and the throwing 

 up of a yellowish mud, quite cold and of an acrid saltness. Over 

 the entire extent the degree of hardness varies with the intensity 

 of the solar rays ; at early morn the whole surface, excepting 

 the centre, is hard, whilst, at mid-day, it becomes so softened as 

 to retain the impression of the lightest impress. Whenever any 

 quantity of bitumen has been dug and taken up from the lake, 

 the excavation soon fills up, and a perfect level is restored within 

 twenty-four or forty-eight hours ; the deeper the digging, the 

 quicker the restoration. In the centre entire trees are sometimes 

 seen emerging to the surface, to be re-submerged soon afterwards 

 by a slow rotatory movement. Casks placed near that spot to 

 receive bitumen, have also disappeared ; and it is reported that 

 strayed animals, venturing too far, have likewise been swallowed 

 up in this vortex. It is evident from the above observations that 

 the operation going on in the Pitch lake may be compared to the 

 ebullition of a thick substance in a large boiler. The asphaltum 

 is thrown up by the active operation of a physical cause constantly 

 at work, and its upward motion prompted by the laws of hydro- 

 statics ; there is also a perceptible sort of regurgitating process. 



