ICO VROF. E, HDLL^ LL.D., P.E.S., T.G.S., ON 



Europe has no parallel in many parts of Western Africa. But 

 changes of climate in a reverse direction after the Miocene epoch 

 can be accounted for by the still later nplieaval which has left 

 the vast deserts of Northern Africa, Arabia, and Central Asia, 

 as clear proofs of the existence of former seas, permitting 

 elephants to live in the long island of Morocco, Algeria, Tunisia, 

 and Malta, and rendering the climate of Siberia milder than at 

 present. 



Geological and physical geograpliy are twin sisters ; their 

 requirements are so intimately united that they cannot be too 

 ■closely associated ; the opening or closing of sea communication 

 between two points, as likewise changes in the elevation of land, 

 finally deviations of ocean currents, materially alter the climate 

 •of the globe, irrespective of all extra terrestrial agencies. 



THE AUTHOE'S REPLY. 



The general concurrence in my views, stated by Professor 

 T. Rupert Jones, is a matter of much gratification. He has 

 touched on one of the points referred to by Colonel Feilden 

 above. 



I gratefully ap23reciate the suggestions of Mr. "Warren 

 Upham in reference to the greater extension of the emergent 

 land in the North Atlantic ai-ea than is shown on my map. I 

 also concur with him that the greater elevation of the land of 

 the American continent had more effect in bringing about glacial 

 conditions in that region than the lower temperature of the 

 Oulf Stream, which more directly affect the climate of Western 

 Europe and the British Isles. 



,. The views stated by the Rev. G. Crewdson seem to me well 

 worthy of consideration, though the subject they open out is too 

 extensive to be discussed here. The depression of the north- 

 western American continent during the elevation of the north- 

 eastern side of the same continent may be accepted as an all 

 but proven fact, and the entrance of large masses of comparatively 

 warm and moist Pacific waters by the enlarged Behring's Straits 

 would doubtless have resulted in abundant snowfall on the Arctic 

 land areas. On the general question regarding the reciprocal 



