1 66 
EXPLORATIONS IN TURKESTAN. 
f» 
COMPARISON WITH AMERICAN FORMATIONS. 
Before leaving the Mesozoic-Tertiary series there is another phase of the subject 
which deserves mention, because of its bearing on the world-relations of the con- 
tinents. The existing physiograjihic features of this portion of Asia bear, as has been 
suggested, a certain resemblance to those of the southwestern jjorlion of the United 
States, the so-called Rasin Range and Plateau provinces. If the rock series and 
the geological events of the one country be compared with those of the other it 
is .seen that while there is considerable difference in details, there is also a significant 
resemblance ; hence the fundamental features of the past, as well as of the present, 
are similar. This is set forth in Table II, where American features which are the 
same as those of Asia are marked " Do." It is not meant to imply that the two 
series of features were identical in time, but merely in sequence. The similarity 
seems too great to be accidental ; it may l)e that we have here the normal sequence 
for an interior desert basin. If this is so we ought to find the same general rock 
series in other desert regions, such as Arabia and parts of the Sahara, where similar 
conditions prevail. 
Table II. — Comparison table of the Mesozoic-Tertiary rock series and of geological 
events in the elevated arid regions of Asia and North America. 
Asia. 
North America. 
Roclu. 
Events. 
Rocks. 
Events. 
6 
7 
8 
9 
10 
11 
12 
Limestone and shale. . 
....Do 
Do. 
Mountain- making and prolonged 
erosion. 
Shales 
Estuarine or playa deposition. 
Conglomerale and 
sandstone. 
Subaerialdeposition. Land slowly 
sinking or stationary. 
. . Do 
Do. 
Slight unconformity. 
Clay shales and coal 
measures. 
Estuarine or swamp conditions . . 
Blue mails 
Elstuaiine conditions. 
Vermilion sandslone, 
cross- bedded. 
Elevation and possibly desert 
conditions. 
... Do 
Do. 
Limestone and gyp- 
sum. 
Depression and return to moraine 
conditions. 
White cross-bedded 
sandstone. 
More rigorous desert conditions. 
Marl and limestone- ■ 
Unstable marine conditions 
Cretaceous coal meas- 
ures. 
Estuarine or swamp conditions. 
Oyster limestone 
....Do 
Do. 
Red and pink beds ■ ■ . 
EUevation and eventually a gradual 
return to subaerial conditions ot 
depositions 
Do 
Do. 
(Pink beds.) 
Brown sandstone and 
conglomerate. 
Complete return to subaerial 
deposition. 
Do 
Do. 
