266 W. N. LOGAN 
in that case, we should expect to find remnants of the former 
beds unless it be assumed that a long interval of time preceded 
the deposition of the Lower Cretaceous. Paleontologic and 
stratigraphic evidence is not in harmony with this assumption. 
The Lower Cretaceous beds of California which are but slightly 
unconformable with the Upper Jurassic, having a closely related 
fauna, are correlated with the Lower Cretaceous of the region 
under discussion.' die 
In many places in the interior region the Lower Cretaceous 
rests conformably on the Jurassic. This tact has been fully 
brought out in the preceding pages. It cannot be affirmed that 
the interior sea first had its connection with the Arctic and then 
gradually spread its waters farther and farther west until it united 
with the Pacific. For if this were true we should find in the 
interior first a fauna composed wholly of. northern species, fol- 
lowed later by a fauna containing both Arctic and Pacific types. 
But no such conditions find expression in the faunal relations of 
the interior. Only one fauna exists in the interior. 
There exists at present no evidence which will support the 
view held by Neumayr,? that the whole of Alaska and all of that 
portion of British America lying north of the interior Jurassic 
area of the United States was submerged during this epoch. All 
that can be asserted positively is that the Aleutian Islands and 
Alaskan Peninsula, in part at least, a narrow margin along the 
Alaskan coast and a wider area in California and Mexico was 
under water, while an arm of the Pacific extended in upon the 
continent from the region of the Queen Charlotte Islands.3 
Lack of communication between the provinces —The Jura of Cal- 
iforniaand Nevada contains a fauna which is very different from 
that of the interior, although the faunas are contemporaneous. 
To explain the difference between the two faunas Neumayr 
assumed that that they belonged to two distinct climatic prov- 
inces. He assumed that the interior fauna was a Boreal fauna 
XSpurr, 15 Cpls. 
2See map p. 267, copied from Erdgeschichte, p. 336. 
3See map p. 245. 
