DENVER & RIO GRANDE WESTERN ROUTE. 65 
out following closely the rocks outcropping in the cliffs. Thus, a 
short distance west of the station at Pueblo the traveler may notice 
on the south (left) that the cliffs are composed of a dark shale, which 
is the bottom bed of the Pierre shale, of Cretaceous age. A little 
farther along a chalky rock rises from below the river, and the dark 
shale can be seen only in the upper part of the cliff, and within a 
short distance it disappears altogether. The chalky rock is the Nio- 
brara, which in many places consists largely of limestone but here 
consists mostly of calcareous shale and thin beds of limestone having 
a total thickness of 600 or 700 feet. Farther west the Niobrara also 
rises to the tops of the cliffs, and near milepost 122, it gives place to 
the Carlile shale, which is about 210 feet thick. Half a mile farther 
on this shale is replaced by a bed of massive limestone (Greenhorn), 
which like the others rises gradually westward in a great fold, de- 
scribed below. Below the Greenhorn limestone lies the Graneros 
shale, which in its upper part contains considerable sandstone in thin 
layers. This formation is 200 feet thick. 
The fold in these beds, which is here cut directly through by 
Arkansas River, has lifted them into a broad, flat dome. The center 
of this dome is marked by a thick bed of sandstone (Dakota), which 
is just brought to the surface near milepost 126 but which the 
river has not yet succeeded in cutting through. The rocks dip 
slightly in all directions from this central part. If the traveler has 
been following the formations from Pueblo he has seen at least 1,200 
feet of rocks rise from below river level. Originally these rocks may 
have formed a large hill at this place, but the river has kept them 
washed away possibly as fast as they rose, and to-day, except for the 
dip of the rocks, there is no evidence on the surface of such a dome. 
From the caiten of the dome near milepost 126 the beds dip up 
the river in the direction in which the train is moving, an and they 
disappear beneath the river in reverse order from that in which they 
appeared on the east. At Livesey siding the Greenhorn limestone 
has reached water level. It soon disappears, and then the beds he 
nearly flat for a long distance. 
All the rocks thus far exposed along Arkansas River except the 
Dakota contain marine shells, which indicate that they were laid 
lawmaking the last Jefferson legis- | tery of Colorado under the act of 
lature passed away. According to | Congress signed by President Bu- 
a Statement in Smiley’s History of | chanan February 28, 1861. . 
Denver, Thus ended the most interesting and 
“Jefferson Territory made its last 
gasp in June, 1861. On the sixth day 
of that month Goy. Steele issued from 
Denver a proclamation announcing the 
arrival of Gov, Gilpin and the insti- 
tution of the Government of the Terri- 
eicinreann endeavor of an isolated 
community to establish and maintain 
within Ra a government of and by 
law that the student of self-govern- 
ment will find in the history of this 
country.” 
