TERTIARY REMAINS. 113 



to consider as abouRcling to an astonishing degi-ee 

 with large animals, because we find the remains of 

 many ages accumulated at certain spots, could 

 hardly boast of more large quadrupeds than South- 

 ern Africa does at present. If we speculate on the 

 condition of the vegetation during those epochs, 

 we are at least bound so far to consider existing 

 analogies as not to urge as absolutely necessary a 

 luxuriant vegetation, when we see a state of things 

 so totally different at the Cape of Good Hope. 



We know* that the extreme regions of North 

 America, many degi'ees beyond the limit where 

 the ground at the depth of a few feet remains per- 

 petually congealed, are covered by forests of large 

 and tall trees. In a like manner, in Siberia, we 

 have woods of birch, fir, aspen, and larch, growing 

 in a latitudet (64°) where the mean temperature 

 of the air falls below the freezing point, and where 

 the earth is so completely frozen that the car- 

 cass of an animal embedded in it is perfectly pre- 

 served. With these facts we must gi'ant, as far as 

 quantity alone of vegetation is concerned, that the 

 great quadrupeds of the later tertiary epochs might, 

 in most parts of Northern Europe and Asia, have 

 lived on the spots whex'e their remains are now 

 found. I do not here speak of the liind of vegeta- 

 tion necessary for their support ; because, as there 

 is evidence of physical changes, and as the animals 



* See Zoological Remarks to Capt. Back's Expedition, by Dr. 

 Richardson. He says, " The subsoil north of latitude 56° is per- 

 petually frozen, the thaw on the coast not penetrating above three 

 feet, and at Bear Lake, in latitude 64°, not more than twenty 

 inches. The frozen substratum does not of itself destroy vegeta- 

 tion, for forests flourish on the surface, at a distance from the 

 coast." 



+ See Humboldt, Fragmens Asiatiques, p. 386 ; Barton's Geog- 

 raphy of Plants; and Malte Brun. In the latter work it is said 

 that the limit of the growth of trees in Siberia may be drawn 

 under the parallel of TO^. 



VoL.I— S K 2 



