Anniversary address op the president. Ixxix 



are thus read by Mr. Darwin : — '' These trees, now elevated to so 

 great a height, have certainly been buried under several thousand 

 feet of matter accuniulated under the sea. They obviously must 

 once have grown on dry land ; and therefore what an enormous 

 amount of subsidence is thus indicated ! As the land, moreover, on 

 which they grew is formed of subaqueous deposits, of nearly if not 

 quite equal thickness with the superincumbent strata, and as these 

 deposits are regularly stratified and fine-grained, not like the matter 

 thrown up on a sea-beach, a previous upward movement, aided no 

 doubt by the great accumulation of lavas and sediment, is also indi- 

 cated." Did the limits I must observe permit, I could lay before 

 you, from this most instructive volume, many other proofs of the 

 oscillations through a vast vertical range to which the South Ame- 

 rican continent has been subject, from a period distinctly traceable 

 back in this southern division of it to the oolitic period, and conti- 

 nuing to the present day. 



One of the greatest outbursts of plutonic rocks, of syenitic granites 

 and metallic veins, in so modern a period, with which we are ac- 

 quainted, has been made known to us by Sir R. Murchison in his 

 work on Russia and the Ural Mountains. The gold which is now 

 collected in so great quantities on the eastern flank of the Ural Moun- 

 tains has been brought to the surface in veins and disseminated 

 through the substance of rocks in this comparatively modern period 

 of geological history. In regard to the subsequent disintegration of 

 these veins and rocks: "the nature of the auriferous shingle, with 

 its subangular fragments, so completely resembles the detritus of 

 lakes, and is so unlike the gravel formed on the shores of seas, that 

 independent of the entire absence of any marine remains whatever, 

 whether of tertiary or recent age, all along the immediate eastern 

 flank of the Ural Mountains, there is no room for doubt that the 

 gold detritus was accumulated during a terrestrial and lacustrine con- 

 dition of the surface*." 



The same author has shown by a large body of evidence, that at 

 the time of the spreading of the northern drift over the then sub- 

 merged comitry of European Russia, the glacial sea was bounded on 

 the east by the then comparatively low chain of the Urals, which 

 formed the rocky shore of a probably low continent on the east, from 

 which powerful streams descended to the west, from the country we 

 now call Siberia. The subsoil of that region exhibits palaeozoic 

 rocks only, covered in part by tertiary accumulations, but without 

 any detritus of the carboniferous or Permian deposits, which cover 

 the more ancient rocks in European Russia. This eastern country, 

 then probably covered with forests, from its inferior elevation and 

 the extension of the northern sea far to the south of its present 

 limits, probably enjoying a climate considerably milder than that 

 which now prevails, appears, from the vast quantities of their bones 

 that are found imbedded in a fossil state over such a vast region, 

 to have been for ages inhabited by large herds of the m^ammoth, 



* Page 492. 



