726 
since much of Wyoming is one continuous 
exposure. After seeing this country, it be- 
comes easy to understand how it was pos- 
sible for a party of the Hayden Survey to 
prepare, in one field season, a reconnais- 
sance map covering as many as 20,000 
square miles. 
The most interesting region of the trip, 
from a picturesque and geological stand- 
point, was that about the Grand Canyon of 
the North Platte. We first saw this from 
the high sage-covered Tertiary crest at 
6,800 feet. Back of us were the rounded 
Indian Grove Mountains of granite, while 
long and dark Ferris Mountain stood on 
our left across the river. Directly in front 
was spread before us, like a painted stereop- 
tican projection, the Grand Canyon country 
of the North Platte. The hills here have 
their escarpment directed towards the west, 
and are superposed like tiles on a roof. 
Beginning on our left were granite hills fol- 
lowed by those of Carboniferous, Triassic 
and Jurassic age, in places partially re- 
peated, and all surmounted by the thick 
Tertiary lake beds. The colors of this 
panorama were pronounced and pleasing, 
especially when freshened by a rain, as 
when we first saw them. The brick-:red 
color of the Triassic contrasted strikingly 
with the light green of the Jurassic and the 
browns of the Tertiary passing upwards 
into ash-colored beds. Hidden in this pic- 
ture across the strike was the Grand Canyon 
of the Platte, eight miles long and in places 
nearly 1,000 feet deep. Over to the right 
may be seen the silver thread of the river 
issuing and flowing through the open coun- 
try, but it is soon lost to view in the Little 
Canyon, which is 400 feet deep and about 
half a mile in length. Both gorges have 
perpendicular right-angled walls, and are 
very narrow, so narrow in places that a 
stone can be tossed across. Only one 
party is known to have gone through the 
Grand Canyon of the North Platte. This 
SCIENCE. 
[N. &. Von. X. No. 255. 
consisted of Freemont with Mr. Preuss and 
‘ five of my best men,’ Canadian voyageurs, 
who started in a canvas boat, August 
24,1842. The passage was extremely dan- 
gerous, and finally, at the foot of a fall, the 
boat was whirled over and men and baggage 
were thrown into the raging stream. 
Luckily no one was drowned, but most of 
the baggage was lost. In the Little Canyon, 
which is through a faulted ridge, there is a 
large hot spring that contains light-green 
algee. This water is now piped half a mile 
to Aleova, where a pioneer has a primitive 
‘ Hot Springs Resort’ fifty miles from a rail- 
road. 
Another very interesting region was Bates’ 
Hole, a narrow hole-like valley in Tertiary 
strata with a maximum depth of 1,500 feet. 
Tt is drained by Bates’ Creek, a tributary of 
the North Platte, near Aleova. The lower 
level is in aseries of delicately tinted yellow, 
red, green, and whitish Eocene shales and 
soft sandstones. Above, along the margin 
of the Hole, are the Titanotherium beds of 
the Lower Miocene, which are picturesquely 
castellated, series above series, in places 
400 feet or more high. This constitutes 
another style of ‘Bad Land’ scenery. Here 
Professor Knight made use of an unusual 
method for ascertaining the time required 
for the erosion of Bates’ Hole. The mar- 
ginal slopes are often very steep, and upon 
them are growing isolated slowly dying 
pines perched by their roots from one to 
three feet above the present surface. Since 
the annual growth rings of the trees will 
indicate their age, a time measure is at 
hand for the amount of strata removed 
from beneath the tree. This, when taken 
in connection with the size of the Hole, 
will give some idea as to its age. A pro- 
visional estimate places it at 1,584,000 years 
since the close of Miocene time. (See Scr- 
ENCE, for October 27, 1899.) 
Several tons of good fossils, mainly in- 
vertebrates, were collected during this trip. 
