Stevenson.] 



108 



[Dec. 2, 



did the natural exposures described in the writer's report on his explora- 

 tions of 1878.* The measurements made at the company's openings are 

 given here as supplementing the observations detailed in that volume. 



The Dillon is the lowest persistent coal bed found in the Trinidad coal- 

 field, and is separated from the Hulymenites sandstone, by but five to ten 

 feet of shale. An opening on Coal canon, tributary to that of the Upper 

 Canadian, shows liie following section : 



coal, but with it is not a little bony stuff, and the whole is strongly pyri- 

 tous. Nos. 4, 6 and 12 are hard pyritous clays. Nos. 8 and 10 are sandy, 

 sometimes becoming hard sandstone. Nos. 7 and 9 are fairly good coal, 

 but contain binders and diagonal streaks of sandstone, which make them 

 utterly worthless. Nos. 11 and 14 are bony stuff, but No. 13 is excellent 

 coal. 



This opening is evidently on the upper division of the bed. The lower 

 division is not exposed. Another opening was run in the Canadian canon, 

 where entries had been driven in both divisions of the bed. The lower 

 division has five benches, all of which yield coal with much ash. No new 

 features were seen in the upper division. The clay overlying the bed here 

 is full of leaf impressions. 



A section was obtained in Dillon's canon at a-deserted opening, just be- 

 low Dillon's ranch. This is described in the writer's reportf upon this 

 region, but the measurements are repeated here to show the general struc- 

 ture of the bed. The section is : 



Upper division 4' 4" 



Carbonaceous shale 0' 4" 



Coal 2' 10" 



Shale 0' 4" 



Coal 0' 10" 



* U. S. Geographical Survey, west of the lOOth Meridian, Vol. iii. Supplement. 

 Now passing through the press. 

 t Log. cit. p. 275. 



