274 REVIEWS. 



stricted within the limits of observation. But in Arago's life- 

 time the evidence was already accumulating which has now 

 proved that in earlier times man and the reindeer lived 

 together on the soil of southern France, when if grapes could 

 ripen in Syria and northern Egypt, dates doubtless could not. 

 Then, at a still earlier day, Palms flourished in Switzerland 

 and Vines in Iceland. Then Maples, Lindens, Plane-trees, 

 Spruces, and Pines formed forests in Greenland uji at least to 

 the eightieth parallel ; and, indeed, our own southern Cypress, 

 or Taxodium — which now barely maintains its existence 

 between the mouths of Delaware Bay and the Chesapeake — 

 flourished along with the Silver Fir of Europe, within two 

 hundred leagues of the North Pole. A climate in Greenland 

 in which Sequoias, now confined to California, Magnolias, 

 Persimmons, and Grapevines were mixed with Maples, Oaks, 

 and Poplars, could not have been colder than, or much unlike, 

 that of Indiana and Kentucky now. 



As w r e have seen, the vegetable world has had an eventful 

 history, and this history Count Saporta undertakes to recon- 

 struct from ancient and authentic documents. 



These documents have settled one point with certainty, 

 namely, that the great changes in the temperature of the polar 

 regions have not resulted from any change in the earth's axis 

 of rotation, such as certain physical geologists have supposed. 

 That this has remained steady throughout the whole period in 

 question is as good as proved by the identity of the miocene 

 and other tertiary fossil plants in all longitudes, from the 

 Mackenzie River and Alaska round to Spitzbergen, Iceland, 

 and Greenland — in part the same species, in all the same 

 or equivalent combinations. Not indeed the same species in 

 the same latitude any more than now, but such latitudinal 

 distribution as to show that the curvatures of the miocene 

 isotherms were quite analogous to those of the present age. 

 Moreover, the monotony which characterizes the sub-polar 

 vegetation of the present day — when the most of the species 

 and the combinations of species occur all round the world — 

 equally characterized it then when clothed with forest trees of 

 a temperate zone. 



