218 Notices of 3/emoirs — Professor A. G. Natliorst — 



Carboniferous System, or again the remains of Saurians, Ammonites, 

 or Nautiloids, in those of Triassic age. But when one bears in mind 

 the extreme richness of the Invertebrate fauna of the Arctic seas 

 to-day, when one remembers the colossal whales which find their 

 subsistence in these waters, one may be inclined to ask if it has not 

 been an error to conclude, from the occurrence of the fossils above 

 mentioned, that the climate was formerly more genial than it is to-day. 

 Should we not be under-estimating the creative power of life if we 

 imagine that-, among the Saurians, the Ammonites, and the Nautiloids, 

 no species has been able to develop which was adapted to life in the 

 Arctic seas? If the Reindeer and the Musk-ox were extinct, who 

 would imagine that these beasts were able to flourish on the scanty 

 vegetation of the high parallels north of 80° of latitude ? And 

 who would suppose that such monsters as the Mammoth and the 

 Woolly Rhinoceros could find sufficient nourishment in the poor 

 vegetation of the Tundras or the Coniferous forests? Such examples 

 teach prudence ; there is certainly no question which requires so much 

 caution as the problem of deducing from the faunas of the past the 

 climatic conditions under which they flourished. 



This remark applies with equal force to the floras. Although 

 to-day the Cycads only occur in warm regions, it would be an error 

 to conclude that the Cycadophyta of the past have always flourished 

 under similar conditions. On the contrary, we must admit that during 

 the Mesozoic period, when these plants were abundant, it would no 

 doubt have been possible to find several species which had adapted 

 themselves to an Alpine climate if such a one had then existed. And 

 if, since then, the differentiation of climates has begun to make itself 

 felt, it would be again a case of overlooking the creative power of 

 life, if Ave assumed that none of the species of Cycadophytes were able 

 to adapt themselves to a temperate climate in the Polar regions. 

 Again we meet with difficulties, even when we study the plants of 

 the Tertiary period, which are assigned to genera still living. Our 

 Common Juniper (Juniperus communis, Linn.), which exists in 

 Northern Europe as far north as the North Cape, exceeds by 20 to 25 

 degrees of latitude, in the Eastern Hemisphere, the northern limit, 

 not only of the other species of the genus, but also the whole family 

 of the Cupressinere. jS'ow, if one imagined that the Common Juniper 

 was extinct, one would naturally draw conclusions relative to the 

 fossil remains from the distribution of the other species. And one 

 would consequently suppose that it lived under a climate much 

 warmer than is actually the case. One would scarcely imagine that 

 we were concerned with a plant adapted not only to temperate, but 

 also to Arctic, climates. (One finds the Juniper, on the western side 

 of Greenland, up to the 64th parallel.) 



Tbese examples counsel prudence, and the matter should be treated 

 with judgment and circumspection. But, even if it is necessary to 

 make reservations, when one seeks to determine from the fossil plants 

 the nature of former climates in the Arctic regions, at least one 

 cannot doubt that they were distinctly warmer than that of the present 

 day. The difficulty of explaining these former climates, especially 

 when one has to take into consideration the length of the winter 



