at 
1895. ] NEW YORK ACADEMY OF SCIENCES. 57 
shale, whose age has not been determined satisfactorily. They 
bear little resemblance to the Permian beds of Texas, but they 
are not far from where the Permian beds ought to be. South- 
ward from Purcell to Davis, about 39 miles, the region is broadly 
rolling prairie without any exposures within a considerable dis- 
tance from the railroad ; but midway between Davis and Dough- 
erty a bold limestone ridge is crossed, whose anticlinal structure 
is well shown in the deep cuts. This ridge is formed of bare 
hills passing within a short distance back of Dougherty. As it 
has a southeasterly trend, it is evidently the anticline passing 
southeast from that place at the junction of Rock and Buckhorn 
creeks. It is crossed by the Denisonand Northern line at about 
6 miles southeast of Dougherty. 
On Buckhorn creek, at about 5 miles from Dougherty, a bed 
of asphaltic limestone was mined as coal some years ago. The 
fragments seen at the pit were so decomposed that the nature of 
the rock could hardly be determined. The bed is about 12 feet 
thick and lies between conglomerates, each about 15 inches. 
Some bright asphaltum, probably gilsonite, occurs in small quan- 
tity. This was used as fuel at Dougherty, but was not satisfac- 
tory. It gave off intense heat, but did not break up, and the re- 
siduum was removed with difficulty. 
The asphalt was seen again near the same stream at about 8 
miles from Dougherty, where prospecting was going on for the 
St. Louis Gilson-Asphaltum Company. The opening is a strip- 
ping along the crop, which no longer exhibits the full thickness, 
which is said to be 14 feet The overlying bed is a conglome- 
rate as at the other exposure, about 18 or 20 inches thick, con- 
sisting mostly of caleareous pebbles, but containing some which 
are silicious and have an onyx-like structure as though they had 
resulted from replacement. A similar conglomerate is said to 
underlie the bed, but it is not exposed at the excavation. The 
asphalt is a tough limestone, very dark brown on the fresh sur- 
face, but becoming gray after long exposure. The distribution 
of the bitumen causes some variation in tint, the lighter color 
prevailing where the bitumen is concentrated along lines and not 
evenly distributed. The percentage of bitumen is reported to 
average not far from 17 and to be as much as 25 in some of the 
samples. It is said to be rather harder than that in most of the 
other asphalts brought to the American market. The bitumen 
fuses when the rock is exposed for several hours to the summer 
sun of Indian Territory, so that the surface of fragments be- 
comes covered with a brilliant coating. Small bunches of bright 
asphaltum, said to be gilsonite, are found frequently. The 
dip at this pit is westward, but the outcrop on the opposite 
