Page:The Journal of geology (IA journalofgeology21894univers).pdf/57

or fir, such as constitute the prevailing arboreal vegetation of that region to-day was recognized in the collections.

In answer to a question concerning the climatic conditions of that region during the Miocene, as indicated by this flora, Professor Lesquereux stated that "by the presence of a large number of Laurineæ the flora becomes related in its general characters to that of a region analogous in atmospheric circumstances to Florida." With this view Professor Lester F. Ward fully agrees, and also Mr. F. H. Knowlton, who has lately given much attention to the flora of the auriferous gravels.

Mr. Knowlton, says "Lesquereux, as already stated, argued that the presence of a large number of lauraceous plants indicated a region analogous in atmospheric circumstances to Florida. From my own studies, which embrace a much larger amount of material than Lesquereux had, I am not only prepared to accept this statement but to show that it was even stronger than he could have made it out."

Florida is a comparatively low country, rising nowhere more than a few hundred feet above the sea, and it is reasonable to infer that during the early gravel period northern California, which was then analogous in atmospheric circumstances to Florida, could not have been a region of high snow-tipped mountains as it is to-day.

It is well known that during the Miocene tropical conditions extended much farther north than now, and under such circumstances it is possible that certain forms of plants may have had considerably greater range in altitude than their relatives in California have to-day.

No doubt the Sierra Nevada existed at that time, but was a very low range, at least in the northern portion, as compared with its present altitude. Yet it was high enough to supply the alder, birch, poplar, and willows, as well as the few pine leaves lately found by Mr. Turner.^[1]

The evidence afforded by the flora of the region is in complete harmony with the inference drawn from the topographic