922 The American Naturalist. [October, 
General Wotes. 
GEOLOGY AND PALEONTOLOGY. 
Faunal Migrations.—An interesting account of the changes in 
the Mesozoic faunal geography of California is given by James Perrin 
Smith in a recent number of the Journal of Geology (May and June, 
1895). These changes the author attributes to migration and points 
out that marine currents along continental borders are favorable to 
migrations. His conclusions, given below, are based on a study of the 
faunal relations of the various series of sedimentary rocks of California, 
and the faunal relations which California had with various regions 
during different periods of geologic history. 
From the data in hand, Mr. Smith concludes that at the beginning 
of the Upper Devonian, some widespread disturbance occurred, opening 
up connection between the American and Eurasian Seas. 
The lower Carboniferous fauna of California was developed directly 
out of Devonian fauna predecessors with the addition of some Eurasian 
elements by migration. 
The Upper Carboniferous fauna was developed directly out of that 
of the Lower Carboniferous, but still with intermigration with the 
Russian and Asiatic regions, so that the California Carboniferous re- 
sembles the Eurasian even more than it does that of the eastern United 
States. 
- The lower Triassic fauna of the West is entirely foreign, having 
migrated in from unknown regions, but having reached nearly simul- 
taneously the western part of America, the Salt Range in India, and 
northern Siberia, but having been cut off from central Europe. 
The Middle Trias of the West already begins to show relationships 
to the Mediterranean province of Europe, showing a connection in 
that direction, while the similarity to the faunas of the Arctic Trias 
province is disappearing. _ 
In the Upper Trias the nearest faunal affinities are with the Hima- 
layan and the Mediterranean provinces. 
In the Lower and Middle Jura there was no connection with Euro- 
pean waters through the Pacific region, but rather through the Atlantic 
or “ Central Mediterranean Sea” of Neumayr, bringing a central Euro- 
pean fauna, 
