330 Miscellaneous. 



an elephant ; it has been called Symborodon bucco. The long- 

 homed species was as large as the Indian rhinoceros, and is called 

 Symborodon acer. The species with three-cornered horns is inter- 

 mediate in size. 



Besides these larger quadrupeds there were myriads of the small 

 ones, whose evident adaptation for insect- and seed-eating habits 

 indicate the abundance of such supplies. Thus there were moles, 

 mice, squirrels, and not less than seven species of rabbits. Areas 

 exist where the beds of the formation laid bare by the weather are 

 found to be covered with the delicate remains of these animals. 

 They cover the surface in such profusion as to resemble the loose 

 grain on the farmer's barn-floor in harvest time. 



The Pliocene stratum, above the Miocene, is usually present in 

 the regions where the latter occurs, though not invariably. It has 

 a more sandy character, while the older beds are more clayey. 

 The life they disclose is quite distinct from that we have just passed 

 in review, differing from it much in the same way that it differs 

 from that below it, i. e. the Eocene. In other words, it is still 

 more like the Hfe of the present time, and the ciirious intermediate 

 or (to speak inaccurately) the mixed divisions have nearly disap- 

 peared. "We have now true dogs and weasels, true elephants, and a 

 few true deers and antelopes. The camels are almost like those 

 now living ; and while the horses have three toes, the side toes are 

 much reduced, and the teeth are much more nearly like those of 

 living horses. Rhinoceroses still abound ; but aU their mixed tapi- 

 roid and elephantine kindred have utterly disappeared. 



A curious feature in the dentition of the horses and camels of 

 this period has been observed. The temporary or milk-teeth of 

 the horses were very much like the permanent or second series of 

 the horses of the preceding or Miocene formation. The second or 

 permanent teeth differed from them, and resembled exactly in type 

 the temporary or milk-teeth of the living horses. The case of the 

 camels is similar. Like the hogs they possessed a full set of upper 

 teeth in front, which they soon shed, thus taking on one of their 

 true camel characters ; but their permanent series all round after 

 this shedding was like that of the milk-dentition of the existing 

 camels and Uamas. In the latter animals the number of the perma- 

 nent teeth is less than that of the first series in one part of the 

 mouth, thus producing another type. 



In the fifth and last period we observe another marked change 

 in the life. Most of the Mammalia are nearly related to those now 

 hving in this and other continents, while a great many forms of the 

 past are lost. Tbe monkeys did not reach into the Pliocene, so far 

 as we know ; now the rhinoceros leaves us. A few remnants only 

 survive of the camels and horses. Oxen first appear either as the 

 giant bison or the southern musk-oxen ; deer of great size exist. 

 The loss is replaced by South-American types, especially gigantic 

 sloths, in great abundance, with droves of tapirs and peccaries. For 

 the first time we have the raccoons and beai's, the latter of the 

 same character as those found with the fossil sloths in Buenos Ayres. 



