176 F. V. Hayden—Hot Springs and Greysers, ete. 
Night and day some of the geysers are in operation continually, 
and, at certain periods, several of them perform at the same 
me. 
about 85 per cent of silica, 11 per cent of water and the remain- 
der mostly chloride of magnesia; and only a slight trace of 
ime was found in the water. In but one locality west of the 
lake, Col. J. W. Barlow found a calcareous deposit. There are, 
scattered over the great area, about forty by fifty miles mn ex 
tent, a few patches of the sedimentary rocks, and it is most 
probable that underneath the deposit of this small group of 
springs, there are portions of the Carboniferous limestone. 
ar as we could ascertain, in all the deposits of the Yel 
lowstone Basin proper, and in the Firehole Basin, silica 18 the 
dominant constituent. The springs are, with ver few excep- 
tions, and those not important, near the borders of the streams 
below any beds of limestone. It is quite possible that under- 
neath the vast masses of volcanic material, which composé 
mountains on every side, the sedimentary rocks exist, but Lam 
disposed to believe that they occur only in isolated and much 
restricted patches, if at all. 
We may therefore state, in general terms, that the great be 
spring region of the sources of the Yellowstone and Missoutt 
rivers 1s covered with rocks of volcanic origin, of comparatively 
modern date. 
In this article I have been able to present only a few of the 
wonderful and most attractive features of this unique tegi0™ 
A bill has been introduced into Congress which has for its pur 
pose the setting apart of tis wonderland as a great National 
Park for all time. We have, as a precedent, a similar acho? 
with regard to the Yosemite valley, and this noble act has met 
We 
that before this article is published to the world the act will 
ave become a law. 
