wAKu.l COLLECTIONS FROM LOWER LARAMIE STRATA. 539 



occurs near the statiou by wliicli the strata on the southwest are lower 

 than those on the ui^rtheast. The coal seams on the east and north are 

 close to the surface and sometimes crop out. They pass downward from 

 south to north with a dip of about 15 degrees, reaching across the mono- 

 cliual valley through which the railroad runs. On the west and south they 

 grow deeper and have mostly ceased to be worked. The fossil plants, 

 ■which are very abundant, are always above the coal, and the strata in 

 which they are richest lie five to ten feet from the highest coal seams. 

 Immediately above the coal is a layer of arenaceous limestone, which is 

 generally shaly, but sometimes solid and very hard (" fire clay"). Even 

 in this a few plants occur, but it was nearly impossible to obtain them. 

 The plant beds proper are fine-grained more or less ferruginous and 

 calcareous sandstone shales, quite easily worked, and from them some 

 beautiful specimens of Cissus, Paliurus, and other genera were obtained. 

 These beds are doubtless somewhat higher than those of Black Buttes 

 and Point of Eocks, but they are probably within the limits of the Lara- 

 mie formation and seem to be the equivalent of the Evanston coal. 



The locality denominated Black Buttes always refers to the station 

 of this name on the Union Pacific Railroad, 140 miles west of Carbon 

 Station and in full view of the black rock from which it takes its name. 

 This had been reduced to a mere section house at the time of my visit, 

 and all traffic was by freight trains. It is in the valley of the Bitter 

 Greek, and typical Bitter Greek strata are alone seen. The railroad here 

 runs nearly north and south. The strata dip to the southeast. Oppo- 

 site the station on the east there are about 100 feet of fucoidal sandstone 

 at the base, above which are two prominent coal seams separated by shales. 

 The coal varies in thickness in both seams and is from three to eight 

 feet thick, the lower seam being perhaps the better in quality. Not more 

 than two feet above the lower coal seam the rocks commence to be plant- 

 bearing. They are reddish on the exposed outer surface, but bluish-gray 

 within, somewhat laminated, and consist of a hard, compact, and very 

 arenaceous limestone. They yield beautifully preserved specimens of 

 leaves, which form the only planes of cleavage. 



Above the upper coal the shales are very thin, and their surfaces, 

 where not exposed to the weather, are generally covered with a profu- 

 sion of very small prints of leaves, stems, culms, fronds, etc., but so 

 fragmentary that little can be done with them. Half a mile north of 

 the station the lower coal seam descends to near the level of the railroad, 

 but the succession of the strata can still be made out. The finest speci- 

 mens found came from beds a mile or more to the northeast of the sta- 

 tion, above a coal mine. The fucoids in the sandstone below the coal 

 at Black Buttes are peculiar and instructive. They seem to consist 

 chiefly of Halymenites major, which is often weathered out so as to ex- 

 hibit good specimens, but more frequently these are incased in concre- 

 tions which attain huge proportions, sometimes having a diameter of 

 six inches. From the ends of these pod-like bodies short sections of 



