1890.] Certain Peculiaritles in the Flora. 221 
Coast shells have not been able to collect land shells near Santa 
Barbara, and yet on the neighboring islands many of these mol- 
lusks are found, notably, a peculiar species of Helix, which, un- 
fortunately, is rapidly being exterminated by the sheep. The 
presence of these shells on the island, and their absence on the 
mainland, I suspect, point the same way as the peculiar distribu- 
tion of the plants, and seem even as significant of the character 
of the change in the climatic condition of the environment. 
The arguments which have been advanced by others to support 
the proposition that our arid deserts were once better watered 
than at present, are not necessary to quote here. That these 
deserts were not always as dry as at present seems to me proven, 
and the zoological facts in the distribution of the island life look 
indeed as if such a desiccation has left its mark on the distribu- 
tion of genera and species. 
In view of the distance of the land of Southern California from 
the sources of glacial cold,’ it seems difficult to suppose that the 
equilibrium of life in this low latitude was much affected by this 
temperature. There are marks of local glaciers on the flanks of 
the Santa Inez Mountains, and the observer has not to go far 
from Santa Barbara to find what may be regarded as their 
moraines, but traces of a continental glacier are believed not to 
exist in this low latitude. These local glaciers may have driven 
hardy forms into the valleys by their advance, but it is hard to 
suppose that to this cause alone a comprehensive change in the 
flora or fauna has resulted. Desiccation of the climate, however, 
is a phenomenon of wide distribution in the south-west, and its 
influence must have been far reaching and great enough to lead 
to wide-spread modifications in the facies of faunas and floras. 
If we ascribe the preservation of the older or partial Pliocene 
flora in the Santa Barbara Islands to their still retaining a moist 
climate from the vicinity of the ocean, it may be asked why the 
adjoining coast, by its situation, is not also acted upon by the 
same influence? Why are not these same plants protected there 
as well as on the island, since the vicinity to the ocean may have 
E oid t z idl 
J 
i that the intensity of the so-called glacial cold 

was not great. 
