162 Messrs. R. C. Taylor a7ul T. G. Clemson on 



fragile, dirty-gray- coloured, argillaceous rock succeeds to the 

 serpentine and alternates with the euphotides. 



Towards Giinnabacon, and indeed throughout a large por- 

 tion of the island of Cuba, the prevailing course or strike of 

 the rocks is about east and west; but in the vicinity of the 

 coal we unexpectedly found that the direction changed to 

 north and south. 



The coal vein of Casualidad is visible at opposite extremities 

 of an excavation thirty feet deep, of a quadrangular form, 

 descending on one side by steps cut in the soft rock or clay 

 which bounds the coal on either side. This soft rock is fra- 

 gile, incoherent, distorted, of a yellowish green colour, like 

 the prevailing euphotides, of which it is a variety. A few 

 feet to the eastward of the vein there occurs a hard blue sili- 

 ceous rock, containing small cavities that are partially filled 

 with a leek-green mineral which we conceive to be a variety of 

 serpentine. 



In close connection with the above, a beautiful diorite oc- 

 curs, the base of which is petrosiliceous, tinged with green, 

 which colour is caused by a mixture of serpentine. This 

 rock is very hard, and has a highly crystalline stiucture. It 

 crops out at several points 



The siliceous rock, the diorites, and the euphotides alter- 

 nate the one with the other. The two first mentioned are in 

 much less proportion than is the third, which is by far the 

 most predominant rock of the country. 



All these are highly inclined, and frequently are vertical ; 

 their direction, as before stated, being north and south, in the 

 neighbourhood of the mine. 



Appearance of the Coal Vein. — The vein commences or 

 crops out immediately under the thin alluvial soil of the sur- 

 face, and follows an irregular, but nearly perpendicular direc- 

 tion downwards, so far as it has been traced, and as shown in 

 fig. 1. 



It is visible to the depth of full thirty feet; but the bottom 

 of the excavation being covered with mud, which had been 

 washed in during the rainy season, we could not readily define 

 the breadth of the vein there ; but it was stated by the over- 

 seer to be nine feet thick. From even this small opening 

 many tons of pure coal had been extracted, and were deposited 

 in a large building adjacent. 



On the north side of the excavation the vein is solid ; having 

 a thickness gradually increasing to four feet at the depth of 

 twenty feet. The coal lies in parallel horizontal layers, of 

 from one to four inches in thickness, across the vein. Some- 

 times these layers appear to have their horizontal position par- 



