388 OLDER MESOZOIC FLORAS OF UNITED STATES. 
the others. The following account will therefore be confined to the 
original collections of Mr. W. H. Reed, sent me by Professor Knight, 
and the two specimens which Mr. Reed sent to Professor Marsh. The 
former of these collections consists of 83 specimens of cycads and 
3 specimens of silicified wood. The specimens of cycads bear the 
numbers 500.1 to 500.83, and those of the wood the numbers 500.85 to 
500.87, of the Museum of the School of Mines of the University of Wyo- 
ming, at Laramie, Wyoming. They are for the most part fragments, 
but there are a few entire trunks. The three largest, Nos. 500.1, 
500.2, and 500.65, though all present, are each broken in two pieces 
which fit together perfectly. In a number of cases complementary 
parts had been detected and, unfortunately for their convenient study, 
glued together. In others such complements had been recognized and 
given the samenumber. It was obvious, however, that many fragments 
that belong together had not been identified, and much time was spent in 
finding and joining these counterparts. This study ultimately resulted 
in finding about 25 such cases. In addition to these there are a num- 
ber which, although they do not actually fit together, nevertheless 
evidently belong to the same trunk, the structure being continuous 
and explicable on the assumption of ite loss of intermediate portions. 
Putting these two classes together, the number of independent trunks 
and fragments is reduced to 61. In several cases more than 2 frag- 
ments belong together; for example, in three cases there are 3 and in 
two cases there are 5 separately numbered pieces of the same trunk. 
A large proportion of the specimens were covered on the side on 
which they lay in the field by an incrustation of lime. This com- 
pletely obscured the structure, and it was necessary to remoye it. 
This was the case with many of the Black Hills cycads, but it pre- 
sented no serious difficulty beyond the labor and expense of placing 
the trunks in a vat of hydrochloric acid and leaving them there until 
the lime was removed, the pure silica of those trunks being wholly 
unaffected by the process. But, as already remarked, the Jurassic 
trunks, although mainly silicified, contain calcareous matter, and the 
acid unavoidably etches the surface somewhat. If this had been all it 
would have been a comparatively small matter. The worst difficulty 
arises from: the fact that the oxidation of the specimens turns the 
parts affected by the acid black or dull brown, and thereby more or 
less obscures the markings of the surface, on which the different 
organs normally have a different shade of color, which brings them 
out distinctly. After the acid bath, although the lime is removed and 
the surface little eaten or injured, all the organs have this uniform 
black or brown color. It is, however, fortunate that, while this inter- 
feres seriously with an ordinary macroscopic examination, the appli- 
cation of a lens removes the obscurity to a considerable degree, and 
