164 Messrs. R. C. Taylor mid T. G. Clemson on 



here, in the strictest sense of the term, a coal vein, unlike 

 any we have before witnessed in any part of the world. It is 

 distinguished from the ordinary deposits of coal, in as much 

 as those occur in distinctly stratified beds, and almost inva- 

 riably exhibit abundant traces of organic remains, for the most 

 part of vegetable origin ; whereas we have before us a geo- 

 logical phaenomenon of no common occurrence, yet whose 

 origin seems sufficiently intelligible. It was evidently, ori- 

 ginally, an irregular open fissure, terminating upwards in a 

 wedge-like form ; having various branches, all of which have 

 been subsequently filled with carbonaceous matter, as if in- 

 jected from below, and that not by slow degrees or by an in- 

 finite succession of depositions, but suddenly and at once. 



This coal is wholly unaccompanied by traces of vegetable 

 remains, or by those beds of bituminous or other shales which 

 almost invariably envelop, cover, or accompany ordinary coal 

 seams, whether in secondary or transition formations. The 

 layers or transverse seams of which we have spoken appear 

 to maintain a horizontal position, that is to say, at right angles 

 to the vein, and when otherwise, the result is accidental, or 

 produced by an after cause. This fact, together with the 

 bacillo-fibrous structure observed, where the coal is in contact 

 with the walls, are among the reasons which lead us to lean 

 towards the supposition that the fissure was charged or filled 

 at once, and that these characteristics are the result of the 

 carbonaceous matter having passed to a more solid state in its 

 present position. 



It would be rash to pronounce an opinion on the presumed 

 extent of this deposit, or to speculate on the probable magni- 

 tude of the vein, below the point at which it is visible at the 

 depth to which we have had access. But if the vein continue 

 to enlarge downwards, in the same proportion as it has aug- 

 mented in the first thirty feet, or even if it holds the present 

 breadth of nine feet, the quantity of this mineral must be very 

 great, and will prove a highly acceptable discovery, so near 

 the precincts of a great and flourishing city, so convenient to 

 the Embarcadero on the sea-coast, and in the midst of a di- 

 strict from which nearly all the timber for fuel has been long 

 since removed. 



Qiiality, — This coal is unusually, light, its specific gravity 

 being commonly not more than 1'142. Two experiments upon 

 heavier specimens, (for the density is by no means uniform,) 

 gave 1189 and 1-197. 



It is perfectly jet black ; having a resplendent lustre, which 

 is much greater in one direction, or under one aspect, than in 

 the other; and it divides into parallel layers in the mass. The 



