84 
By Dr. F. B. SUMNER 
Scripps Institution for Biological Research. 
A record of my impressions on the excursion across San Diego 
county would, I fear, have little more seientifie value than the jottings 
of any tourist or sightseer. To a geologist or ecological botanist this 
trip must have furnished unlimited possibilities of observation and in- 
terpretation. For the landscape itself consisted of nothing but geology 
and botany—of mountains and cliffs, of forest, chaparral and desert. 
But where were the animals? Doubtless the ornithologist saw a bird 
of interest in every tree and shrub, but there was no ornithologist in 
our car. A herpetologist night have recognized the occasional lizards 
which scurried away over the rocks on our approach. Or an entomolog- 
ist might have taken much satisfaction in noting the ants or beetles 
which were characteristic of the various sections of our route. But few 
zoologists would probably have added much to their knowledge of ani- 
mal life. 
However, I am not arguing that such a trip is profitless, even to 
a zoologist whose work does not le in any one of the special fields men- 
tioned. If he does not learn much regarding animals, he learns a great 
deal regarding the world in which they live. Considered as a succession 
of animal environments, this cross-section of Southern California is 
surely as instructive as it 1s spectacular. One does not need meteoro- 
logical instruments to detect the change from the cool moist air of the 
coast to the warm, dry atmosphere of the plateau, and thence to the 
scorching winds of the desert. And even in this, the dry season of the 
year, one could judge pretty well by the vegetation of the comparative 
annual rainfall of the regions traversed. One who makes this trip for 
the first time is given a truly startling demonstration of the screening 
etfect of the great mountain wall in determining the aridity of the in- 
terior valley. This picture, to be sure, is not so diagrammatically clear 
in the neighborhood of Mountain Springs as it is in the Laguna Moun- 
tains, a little further north. 
Our car was unluckily separated from the rest of the party early 
in the trip, but we were so fortunate as to have some most congenial 
associates, Including two botanists and a geologist. 
