SOUTHERN CALIFORNIA ACADEMY OF SCIENCES. gi 



migrated from this continent to those far distant tropical re- 

 gions? Or, did they come from those regions by way of s(Mnfc 

 land connections which have since been obliterated by cosmic 

 changes f With a few exceptions we know of no animals which 

 have lived on this continent from which by any known law 

 or process of evolution, they could have come. Nor have they 

 left any descendants which can in any way be traced back 

 to them as progenitors. 



One of the above named exceptions is the Horse, whose 

 original home seems to have been on this continent, and of 

 Avhich family nearly fifty fossil species have been found in the 

 [Tnitod States. These have been traced back to the time when 

 they had three, four and fiA^e toes to their feet. Some of the 

 species referred to were only \\\o feet high, and one, the 

 Eohippus of Marsh, was no larger than a fox, and is the oldest 

 known animal of which is clearly referrable to the horse 

 family. 



The evolution of this aninuil has been clearly traced 

 through the Eocene, Miocene and Pliocene periods, but it 

 seems to have disappeared at some time during the Quarter- 

 nary. It probably migrated to other continents by the i-oute 

 followed by other animals in coming to our continent, as it was 

 only re-introdueed in America since written history began. 



■ PROTOHIPPUS. 



Two species of the Protohippus (allied to the horse) have 

 been found in California, one named Protohippus insignis, by 

 Leidy, beneath the lava of Table Mountain, Tuolumne County, 

 at a depth of two hundred and ten feet ; another at a depth 

 of sixty feet in Southern California, is probably a different 

 species. (Dr. J. G. Cooper). 



MASTODON. 



The writei' in his explo)-a tions in Central California discov- 

 ered two or more species of the Mastodon in rocks of Pliocene 

 age. The other large mammals treated of in this chapter were, 

 mostly, so far as known, confined to the Quarternary, or Post- 

 Tertiary. 



It is possible that some of the extinct animals whose re- 

 mains have been found in Quarternary deposits lived in Piio- 



