THE 



GEOLOGICAL MAGAZINE. 



NEW SERIES. DECADE II. VOL. II. 



No. XL— NOVEMBER, 1875. 



OIR-IGrlZKT^IIL ARTICLES. 



I. — Ojst the Former Climate of the Polar Regions. 1 

 By Prof. A. E. Nobdenskiold, For. Corr. Geol. Soc. Lond., etc., etc. 



^NLY a few years ago it was looked upon as an article of faith 

 among geologists, that the whole globe was once in a melted incan- 

 descent state, and that the conditions of temperature now prevailing 

 on the surface of the earth have been in process of time produced 

 by the slow gradual cooling of the once fused and glowing mass. 

 It then appeared so natural that, in consequence of the earth's in- 

 ternal heat, a tropical climate should extend from pole to pole, that 

 no special weight was attached to the evidences of this fact which 

 geology was at that time able to produce. The Dane Giesecke's 

 and the English Scoresby's specimens of fossil plants from the east 

 and west coasts of Greenland, evidencing a warm climate there, 

 attracted so little attention, that neither they, nor the fossil re- 

 mains of Saurians found by the famous Arctic traveller Sir Edward 

 Belcher in the American Polar Archipelago, could be found in the 

 museums to which they had been confided. 



It was not till geologists had become fully convinced that the 

 gradual transition from the time when a warm climate was supposed 

 to have prevailed over the whole earth and the present time has at 

 least once been interrupted by a period during which the greater 

 part of the European and American continents were covered by 

 mighty glaciers, that the geological theory of climates was taken up 

 with real interest. People began gradually to perceive that, even 

 supposing the earth really to have once been in a state of glowing 

 fusion, the cooling must already at the Cambrian and Silurian 

 epochs have proceeded so far that the quantity of heat which the 

 earth lost by radiation was fully compensated by that which it re- 

 ceived from the other heavenly bodies. It has also been supposed 

 that the cause of the Glacial period — when vast ice mountains scat- 

 tered boulders from Scandinavia over the plains of Northern 

 Germany, and when the Swiss Alps formed the centre of an icy 

 desert similar to the present Greenland — is to be sought for in some 

 trifling changes in the form of the earth's orbit and the inclination 

 of the Equator, which have taken place, and continue to take place., 

 periodically after the lapse of thousands or hundreds of thousands 

 of years. The same causes which have once produced the Glacial 



1 A Lecture delivered at the Anniversary Meeting of the Eoyal Swedish Academy 

 of Science, March 31, 1875. 



DECADE II. — VOL. II. — XO. XI. 34 



