JANUARY 11, 1901.] 
led a solitary life. The construction of 
both teeth and feet teaches you whether it 
lived in the water, along the shores and 
swamps, in the meadows or on the dry 
grasses of the uplands and mountains. If 
an animal is found with short crowned 
teeth and spreading feet and its remains are 
always imbedded in coarse sandstones and 
gravels, you have an absolute demonstra- 
tion that it lived and died near the river 
bank, if on the other hand the teeth are 
long crowned, adapted to the grasses, and 
the limbs are stilted like those of the ante- 
lope, you infer that it avoided water courses 
and that its remains were deposited in the 
fine dust like that now seen upon our 
western plains. This law has been re- 
cently used for a geological generalization 
by Dr. W. D. Matthew, which, if confirmed, 
will entirely overturn the lake-bottom 
theory long held for certain great forma- 
tions of the Oligocene and Miocene east of 
the Rocky Mountains, as shown in this 
map.* It will bring in its train a whole 
series of consequences, because a new idea 
disturbs the relations of old ones just as 
the introduction of a new animal into a 
country may alter the whole balance of 
life. It will change our views, not only as 
to these eastern deposits, but as to the 
climate of this period; this which we have 
always supposed to have been extremely 
moist, will now prove to have been dry, not 
so dry as upon the western plains of the 
present day, but certainly as dry as in great 
districts in Africa. These fine dry subaérial 
or eolian deposits of drifting soil, containing 
animals of one type, are traversed by sand- 
stone deposits due to intersecting rivers and 
containing animals of quite another type. 
This result has not been reached haphazard, 
but it is largely due to the exact study of 
extremely exact field records which are now 
made as to the level at which every speci- 
men is found. The kind of rock in which 
* Oligocene Lake. 
SCIENCE. 
47 
a skeleton is found and even its position 
often forms a clue to its mode of deposition. 
Thus paleontology works hand in hand 
with geology and throws a clear light upon 
the climatic conditions of the past. 
In line with zoology is the adaptation of 
extinct types. The very first advice I give 
to my students is to ponder over the func- 
tion, purpose, fitness or adaptation of parts. 
Comparative anatomy and paleontology are 
alike dry where they ignore physiology, 
they become fascinating in the measure 
that they reveal design. Consider for a 
moment the story told by these vertebre, 
part of the backbone of a great dinosaur of 
50 to 70 feet in length; they are marvels of 
construction, with all the beauties of the 
flying buttress of a cathedral and rigidity 
of the T truss of a modern bridge; evidently 
the mechanical problem which this animal 
solved was to combine the maximum of 
size and strength with the minimum of 
weight. 
This spirit of looking for ‘ purpose’ and 
ignoring the conventional distinctions be- 
tween a petrified animal and a living one has 
been more or less characteristic of the work 
of the master minds of paleontology from 
the time of its great founder Cuvier, of 
Cuvier’s successor, Owen, and of our own 
Cope. Did not Cuvier propose the law of 
correlation, whereby he maintained that a 
single claw would enable us to give the 
habits and restore an entire animal? A 
generalization, not altogether supported by 
more recent evidence, which in his day ex- 
cited great admiration and called forth the 
famous remark of Balzac that ‘ Cuvier like 
Cadmus builds cities from a single tooth.’ 
The masters of every science are always in 
advance of the lesser men, many of whom 
are seeking a bubble reputation, not at the 
cannon’s mouth, but by the laborious de- 
scription of new species. Systematic de- 
scription is at once the staff of our progress 
and the bane of our existence. Rightly 
