128 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 
[Yol. V. 
grained sandstones. Higher up conglomerates occur, and still higher 
coarse conglomerates and breccias prevail. Interbedded with the mas- 
sive, irregular beds of the latter rocks are always thin layers of sand- 
stones and shales. The sandstones are fine-grained, thinly bedded, and 
contain more or less tufaceous material. Their prevailing color is green- 
ish and greenish-gray. They are apparently composed chiefly of m aterials 
derived directly or indirectly from volcanic sources. In no case are 
pebbles of quartz or other granitic constituents found in either the sand- 
stones or conglomerates. 
The exposures of strata in the first three or four hundred feet at the 
base are not good, and but few of the silicified trunks appear above the 
covering of vegetation. At the height of 500 feet, the occurrences be- 
come very numerous, and the great size and fine state of preservation 
of many of the trunks was a matter of much surprise. Prostrate trunks, 
50 and GO feet in length, are of frequent occurrence, and not a few of 
these are as much as 5 or 6 feet in diameter. 
The standing trunks are generally rather short, the degradation of the 
compact enclosing strata being so slow that the brittle trunks break 
down almost as fast as they are exposed. In many cases the roots are 
exposed, and may be seen penetrating the now solid rock with all the 
original ramifications One upright trunk, of gigantic proportions, rises 
from the enclosing strata to the height of twelve feet. By careful meas- 
urement it was found to be ten feet in diameter, and as there is nothing 
to indicate to what part of the tree the exposed section belongs, the 
roots may be far below the surface, and we are free to imagine that 
there is buried here a worthy predecessor of the giant Sequoias of Cali- 
fornia. Although the trunk is hollow, and partly broken down on one 
side, the woody structure is perfectly preserved, the grain is straight, 
and the circles of growth distinctly marked. The bark, which still re- 
mains on the firmer parts, is four inches thick, and retains perfectly the 
original deeply lined outer surface. Specimens of the wood and bark 
were collected, but no microscopic examinations have been made. It is 
clear, however, that the tree was not a conifer. The strata which en- 
close this trunk are chiefly fine-grained greenish sandstones, indurated 
clays, and moderately coarse conglomerates. They have been built 
around it as it stood in comparatively shallow, but doubtless quiet waters. 
As would naturally be expected, these strata contain many vegetable 
remains : branches, rootlets, fruits, and leaves are extensively enclosed. 
One stratum of sandstone that occupies a horizon nearly on a level with 
the present top of the giant tree contains a great variety of the most 
perfectly preserved leaves. Such specimens as we were able to bring 
away with us have been submitted to Professor Leo Lesquereux for 
identification. They are found by him to belong to the Lower Pliocene 
or Upper Miocene, and correspond in a number of their species with the 
Chalk Bluffs specimens of Professor Whitney. They include — 
Arabia Whitneyi , 
Magnolia lanceolata , 
