ARTESIAN WELLS IN COLORADO. 537 
have a fair chance to carry out their theories and ideas—they have publicly an- 
nounced them, and until their failure or success proves them right or wrong, it is 
not fair to find fault. But while anxiously awaiting the final result that their bor- 
ings will develop, we will examine the question of such wells in the abstract, and 
discuss not only the origin of the underground supplies of water we may expect 
to reach in Colorado, east of the main mass of the Rocky Mountains, but the 
constant proportion that the subterranean supply of water bears to the total mete- 
-oric supply—the amount that is carried out into the open plains country by evap- 
oration and the streams, and lastly the topographical and geological features, fa- 
vorable or unfavorable, to the project of a water supply from artesian wells. 
Originally, we conceive that as late as the lower Eocene or upper Cretaceous 
ages, the whole region between the South Platte and Wahsatch Mountains was then 
an undulating surface, unbroken by any mountain range. The Rocky Mountains 
were then elevated, and on their flanks to the east and from the central range 
westward to the great basin the cretaceous strata were tilted and uplifted in great 
confusion. This continuous movement of elevation raised up on the east foot-hills 
into the jurassic and triassic and carboniferous strata existing underneath the Cre- 
taceous, so that we can to-day walk over and examine each outcrop from the 
Eocene to the Carboniferous without difficulty, and each lying in a highly inclined 
position from the thirty-fifth to the seventieth dip. / 
Most prominent among the successive outcrops that we find parallel to, and 
continuous from the North Platte to the Spanish peaks, are the various high pic- 
turesque ridges of cretaceous sandstones and slates that like vast waves follow the 
contour of the granite and mica slate foot-hills, whose elevation originally disturb- 
ed their normal level with the most recent Cretaceous—or we might better say at 
the point of passage from the upper Cretaceous to the lower Eocene we find a series 
of formations, essentially fresh water, or estuary too in part, in which are devel- 
oped a large succession of coal veins, accompanied with a large development of 
fire-clay and potters-clay beds, and finally overspread with a very thick deposit of 
green Tertiary clay, lying uncomformably upon the coal measures. 
Now the inclination of the successive strata from the metamorphic eastward 
to the tertiary is excessive, and the ends of the strata form the general surface of 
the ground in the valleys and the foot-hills, each branch or affluent of the Platte 
cutting a bed through the upturned strata until it reaches the more horizontal 
formations that constitute the Missouri and Platte river prairies, while a large 
portion of the water that comes from the central range in the shape of melted 
snow or summer rains is taken up and stopped by the more porous and open | 
sandstone strata that form the beds of the streams when they leave the mountain 
cafions on their way to the South Platte, the North Platte, and the Arkansas. 
This amount of water from the streams whose supply comes from the central 
range, joined to that which, as melted snow and as rain, is taken up and absorbed 
all over the foot ranges of our mountains, finally reaches our porous sedimentary 
strata at the foot of the mountains, and follows down their fissures and faults 
until they either reach the impenetrable fire-clay walls of our coal formation, or 
