428 Mr. J. Croll on the Change in the Obliquity of the EcKptic, 



climate much warmer than its present one. He states that it is 

 quite impossible that the trees found at Atanekerdluk could ever 

 have nourished there if the temperature were not far higher than 

 at present. The difference must have been at least 29° F. Nor 

 were the trees found here all at the extreme northern limit of 

 their growth ; for in the Miocene flora of Spitzbergen, lat. 78° 

 N., we find the beech, plane, hazel-nut, and some other species 

 identical with those from Greenland. And we may conclude, he 

 thinks, that the firs and poplars which we meet at Atanekerdluk 

 and Bell Sound, Spitzbergen, must have reached up to the North 

 Pole if land existed there in the Tertiary period. 



The Sequoia Langsdorfii is the most abundant of the trees of 

 Atanekerdluk. The Sequoia sempervirens is its present repre- 

 sentative. This tree has its extreme northern limit about lat. 

 53° N. For its existence it requires a summer temperature of 

 59° or 61°. Its fruit requires a temperature of 64° for ripen- 

 ing. The winter temperature must not fall below 34° ; and that 

 of the whole year must be at least 49°. The temperatures of 

 Atanekerdluk during the time that the Miocene flora grew could 

 not have been less than the above-mentioned. " These conclu- 

 sions," says Professor Heer, " are only links in the grand chain 

 of evidence obtained from the examination of the Miocene flora of 

 the whole of Europe. They prove to us that we could not by any 

 rearrangement of the relative positions of land and water produce 

 for the northern hemisphere a climate which would explain the 

 phenomena in a satisfactory manner. We must," he continues, 

 u admit that we are face to face with a problem whose solution 

 in all probability must be attempted, and, we doubt not, com- 

 pleted by the astronomer." 



But, more singular still, at a period not anterior at least to 

 that of the boulder-clay, a condition of climate prevailed in arctic 

 regions much warmer than at present ; for the remains of an- 

 cient forests have been found in places where at present nothing 

 is to be seen but fields of snow and ice, and where the mean 

 annual temperature scarcely rises above the zero of the Fahren- 

 heit thermometer. 



A trunk of a tree was discovered erect as it grew, by Captain 

 Sir E. Belcher, on the 12th of September 1853, to the north of 

 a narrow strait which opens into Wellington Sound, lat. 75° 32' 

 N., long. 92° W. The trunk was dug up and brought to Eng- 

 land and examined by Dr. Hooker, who pronounced it to be a 

 species of white spruce, Pinus (Abies) alba*. The remains of 

 •an ancient forest were discovered by Captain M'Clure in Banks's 

 Land, in lat. 74° 48', extending along a range of hills varying 

 from 350 to 500 feet above the sea, and from half a mile up- 

 * British Association Report for 1855, p. 101. 



