386 OLDER MESOZOIC FLORAS OF UNITED STATES. 
is supposed to belong to the Trias. The marine J urassic rests upon 
this, and over it is the fresh-water Jurassic, which every where 
throughout this region holds saurian bones. The whole is capped by 
a formation which is called Dakota, but which in all essential respects 
resembles the Lower Cretaceous of the Black Hills. In some places, 
however, it has a different appearance and can be compared with 
phases of the Kansas deposits underlying the Dakota, especially as 
exposed at the head of the Medicine Lodge River." 
The cycad locality is in the northern portion of the hills and only half 
a mile from the cabin, and is located on section 13 of the township 
and range above mentioned. It occupies a rectangular area some 300 
yards long east and west and 50 yards wide north and south, a little 
below and on the north side of the summit of a low rounded ridge in a 
sort of gap near the west end of the most northerly spur of the Freeze- 
out Hills. This spur is much higher to the east of this gap, with a 
western scarp like the rest, and is capped by Cretaceous rocks, as shown 
in the section opposite. It lies near the middle of the fresh-water 
Jurassic. The cycadean trunks are buried in a loose and soft reddish- 
gray calcareous sand, easy of excavation, and a considerable number 
were dug out with a mattock. There are doubtless many more beneath 
the surface, and Professor Knight proposed to have the entire area 
turned over with a subsoil plow in the hope of bringing them to light. 
This loose calcareous sand is so different from the material on the 
ridge above and below the cycad bed as to make it apparent that it con- 
sisted of a disintegrated stratum which was unlike those of the under- 
lying and overlying beds, and I set about tracing it to the east, where 
the northern slope of the spur is much steeper and the strata are better 
exposed. I had no difficulty in doing this, and soon found the bed well 
exposed and continuing uniformly through the hill on its northern flank. 
It forms a ledge much of the way, and consists of a coarse, reddish- 
brown, cross-bedded sandstone with streaks of small, white, calcareous 
flecks, or small pellets. In some places these pellets are larger and give 
the rock somewhat the appearance of a conglomerate. There are also 
black carbonaceous streaks, containing compressed bits of lignitized 
wood, Silicified wood is very abundant in the cycad bed proper and is 
occasionally seen in the ledges. 
After familiarizing myself with this important stratum I crossed over 
to the low hills north of the valley in which the cabin is located, and 
found it occupying the summit of some of them. It is much thicker 
there and forms crags. No cycads were found there, but large trunks 
of silicified wood lie embedded in the rock, and the gulches below are 
strewn with them and with blocks of the wood that have weathered out. 
1See Science, new series, Vol. VI, Nov. 26, 1897, p. 815, and the paper of Mr. C. N. Gould On aseries 
of transition beds from the Comanche to the Dakota Cretaceous in southwest Kansas: Am. Jour. Sci., 
March, 1898, 4th series, Vol. V, pp. 169-175. 
