KUSSELL.l TUFF CONES AND CRATERS. 73 
designate what may be said to be sand and gravel produced by vol- 
canic explosions. This finer and usually exceedingly rough material, 
when more or less consolidated, passes under the general name " tuff." a 
Mingled with the tuff, and also due to explosions, are fragments and 
rough masses of scoriae, volcanic bombs, and thin, irregular, cake-like 
forms of lava. 
The number of elevations composed of fragmental material of the 
nature just referred to can not be definitely stated, as the older ones 
have to a great extent been broken and more or less completely 
destroyed by the explosions to which the younger ones owe their exist- 
ence. Several of the more perfect cones and craters stand on the ruins 
of older volcanoes, and many rounded hills of lapilli, smoothed by the 
wind, are evidently portions of craters which have lost their character- 
istic shape. Possibly there are 20 craters either complete or in what 
may be termed a fair state of preservation, but portions of perhaps as 
many more may be seen, either isolated or partly buried beneath later- 
formed piles of fragments. In one place, about a mile northwest of the 
highest of the buttes, more than half of a crater approximately 150 
feet high has been removed, probably by explosions, and three conical 
depressions, with circular rims of lapilli, have been formed on the site 
of the ruined part. In certain instances, also, large portions of once 
perfect craters have been floated away by the lava which flowed from 
them. About the more conspicuous cones and craters still remaining, 
and especially to the north of the most prominent butte, there are 
extensive fields and rounded hills of lapilli which were evidentl}' formed 
by showers of fragments carried to a distance from the volcanoes which 
produced them and deposited in broad undulating heaps. These 
smooth fields and low, rounded hills are in striking contrast with the 
frequently rough and angular surfaces of adjacent lava streams, and, 
like the tuff cones, present many pleasing variations in color, ranging 
from deep red through brown and purple to lusterless black. The older 
members of the Cinder Buttes are covered with grass and support an 
open forest of pine and fir, but the } T ounger ones and the younger lava 
streams which flowed from them are entirely bare. The trees in most 
instances are rooted in loose deposits of lapilli which have not decayed 
sufficiently to form what may be termed soil, but this deficiency has 
been supplied by dust brought by the wind, or by the volcanic dust 
showered on the coarser deposits during late eruptions. 
The highest of the Cinder Buttes rises as a prominent conical mass 
of reddish and black lapilli to a height of 600 feet above the surround- 
ing plain and is far more prominent than aiw of its neighbors. About 
its base the rims of some five or six older volcanoes may still be seen. 
oThe term tuff, as here defined, is to be distinguished from tufa, the deposit formed by certain 
springs. 
