536 KANSAS CITY REVIEW OF SCIENCE. 
only for the introduction of mammalian life, but even for giving to the landscape: 
its existing features. It seems indeed strange that no precursors of the Eocene 
mammals have yet been found in connection with these plant remains of the newer 
cretaceous. There is a gap here in animal life which we may expect at some 
time to be filled. There seems, however, notwithstanding the great changes in 
climate and physical geography, to have been much less change from the creta- 
ceous onward in the plant world than in the world of higher animal life, so that 
Saporta can figure series of leaves of plants of modern genera from the Eocene 
upward, showing so little modification that they may in some cases be regarded 
as scarcely more than varietal forms, while some of the species have undoubtedly 
survived without change through all the long ages extending from the beginning 
of the Kainozoic to the present day. Plant-life is in this analogous to the lower 
animal life of the sea, which presents the same unchanged characteristics in 
Eocene and Modern species. 
(Zo be continued.) 
ARTESIAN WELLS IN COLORADO. 
CAPT. E. L. BERTHOUD. 
An artesian well is one that is sunk through an inclined stratum of rock or 
clay, or slate impervious to water, to more porous or pervious strata underneath. 
_ Hence, unless we have inclined strata, or those inclined qua-quaversally, thus. 
forming boat-shaped or saucer-shaped depressions, we cannot hope to succeed in 
sinking an artesian or water pressure well. 
The increasing volume of population that is surging west of the Missouri 
river into what Professor Powell justly calls the arid regions of the United States, 
and the increasing and imperative demand that this swelling tide has for an 
abundant and perennial supply of water, is one that justly demands immediate 
and paramount attention on the part of State, local, and (above all) general gov- 
ernment authorities. 
It is not the design here to enter into any details of where and how we must 
or do use water, but simply to discuss the subject of water supply in its various 
forms as evident to us—the causes that affect its volume and distribution, and the 
methods that in future may be used to enhance its supply and to render desert 
wastes habitable and of economic value. 
Prominently before the people of Colorado is Senator Hill’s appropriation 
(for to his efforts this is mainly due) that has been made for the purpose of sink- 
ing artesian wells in Colorado, as a trial experiment. 
We will not in this sketch pretend to criticise the action of the ‘‘ experts” 
who have decided upon the localities where our wells are to be sunk—nor do we 
design these remarks in any unfair spirit of criticism. The gentlemen, who have 
for the department in Washington the care and responsibility of this work, must 
