Geological Causes of the Scenery of Yellowstone Park. 161 
The character of the country is due in the next place to the 
fact that it is new. This is evident even to those who are not 
geologists. Nearly all the other parts of the United States 
were completed before the Yellowstone region began to take 
its present form. The Gallatins, the first range to be seen up- 
on entering the park, furnish a good example of the history 
of the region. Upon Archaean granites, schists, and gneisses 
which subsequent operations have exposed to view, were de- 
posited the quartzites, sandstones and limestones of the Silu- 
rian. These were followed, in a slow, quiet, uneventful man- 
ner by the schists, clays, sandstones, and limestone of the Car- 
boniferous, Jura-Trias, and the Cretaceous. At different 
places in the park the siliceous and shaly limestones of the 
lower, middle, and upper Cambrian, the characteristic rocks 
of the Devonian, and the typical subdivisions of the Cretaceous 
— the Dakota, Colorado, Montana, and Laramie — are exposed. 
These rocks were laid down conformably. Then came a peri- 
od of intense disturbance. The peaceful course of events was 
changed. The sluggish, phlegmatic plains were shaken, up- 
turned, and made into heroic mountains. The southern end 
of the Gallatin mountains was raised. A sharp fold occurred 
between Electric peak and Cinnabar mountain. The axis of 
the general fold trends northwest and southeast. This eleva- 
tion and folding of the rock masses caused the layers to crack 
and fault — to slip past each other like the river ice at spring 
thawing — so that the resulting mountains were filled with 
crevices and passage ways leading to great depths. Some por- 
tions of the earth mass underneath relieved of pressure expan- 
ded, passing from potential to actual liquidity. This molten 
material was crowded up through the passageways filling 
them, crowding between the layers of fissile strata forming 
lacolites and sills, and pouring out upon the surface in enor- 
mous floods. There were definite, well marked periods of 
cracking and flooding. 
What the novel is to human life the geological story is to 
geological occurrence. In an hour's reading the novel pre- 
sents the events of a life time, but human experience teaches 
the proper interpretation. A geological description presents 
in a fewminutes the events of a myriad of years and human 
experience is unable to disclose the proper perspective. The 
