INVESTIGATION OF TEMPERATURE CHANGES. 247 



Proboscidcc possessed a remarkable capacity for enduring changes of tempera- 

 ture, it is nevertheless certain that their remains are found in abundance in 

 reo-ions where, at the present time, the vegetation is by no means sufficiently 

 luxurious, or of a character suitable for the support of such large animals. 



The following are the conclusions drawn by Mr. S. H. Scudder from an 

 examination of the fauna of the Tertiary lake-basin at Florissant, in Colorado, 

 fiimous for its prolific beds of plants and insects, and situated in a narrow 

 valley high up in the mountains at the southern extremity of the Front 

 Ran"-e of the Rocky Mountains, at no great distance from Pike's Peak, in 

 latitude 39°: "Florissant itself is situated 2,500 meters above the sea, and 

 the presence of so considei'able a number of white ants embedded in its 

 shales is indicative of a much warmer climate at the time of their entomb- 

 ment than the locality now enjoys. Investigation of other forms increases 

 the weight of this evidence at every step, for nearly all the species (very 

 few, certainly, as yet) which have been carefully studied are found to be 

 tropical or subtropical in nature."* 



Abundance of evidence of a kind similar to that given above for our own 

 western regions is at hand from various other portions of the world. Noth- 

 ing can, however, be brought forward of so striking a character, in reference 

 to changes of climate since the Tertiary period, as that which has resulted 

 from the various expeditions to the north pohir regions during the past few 

 vears. The facts are so well known, and have been so fully laid before the 

 public in a variety of accessible forms, that it is not necessary to do more 

 tlian briefly state the general scope of the deductions drawn by eminent 

 authorities who have worked up the material brought from high northern 

 latitudes, and especially by ITecr, in whose hands most of the fo.ssil plants 

 have been placed for examination and description. 



Before alluding to the climate of Tertiary times, within the Arctic Circle, 

 as manifested by the richness of the vegetation prevailing over that region 

 during that period, brief notice may be taken of the pi-oofs of a much warmer 

 climate there at an epoch much more remote than tliat. The existence at 

 various localities, in the very highest northern latitudes yet visited by man, 

 of the fauna and flora of the Carboniferous epoch, shows most conclusively 

 that a warm and equable climate prevailed over the earth at that distant 

 period, and that this condition of things was not something peculiar to the 

 Tertiary epoch. The geologists of the last English expedition, under Captain 



* Bul'.etin of the U. S. Geol. and Geog. Suvvey of the Territories, Vol. VI. p. 299. 



