ANNIVERSARY ADDRESS OF THE PRESIDENT. 195 



Arctic Ocean, which they were the first to discover. In ascending 

 the Dwina, which flows into a bay of the Icy 8ea at Archangel, 

 they discovered at about 150 miles from that city, near where the 

 Vaga, a tributary, falls into the Dwina, a profusion of shells having 

 a very modern aspect, regularly imbedded in clay and sand of about 

 ten feet in thickness, which, covered by about twenty feet of the 

 coarse gravel and detritus of the country, reposed on red and white 

 gypsum, subordinate to red marls of the Permian system of rocks. 

 They traced these shelly beds to a distance of about eight miles. 

 Some of the shells preserved in the blue clay or marine sand, and 

 thereby excluded from atmospheric influence, have retained all the 

 freshness of their original colour, with their valves often united ; and 

 the whole, even when blanched, are generally in a good state of pre- 

 servation. What they collected were carefully examined by skilful 

 conchologists. Dr. Beck of Copenhagen considered all he examined 

 to be identical with those now existing in northern seas which range 

 from 42° to 84° north latitude. Mr. Smith of Jordan-hill was of 

 opinion, that though many of these species are recent, some are of 

 peculiar varieties, now found in desiccated and elevated sea-beaches 

 only. Mr. Lyell recognised the group as identical with that which he 

 had described from Uddevalla in Sweden, a distance of a thousand 

 miles from the Dwina ; and Mr. G. Sowerby stated, that the shells, 

 though on the whole an association of existing species, have yet 

 among them forms seldom, if ever, found except in raised sea- 

 bottoms of a subfossil character. The authors estimate the place 

 where these shelly beds occur to be about 150 feet above the sea at 

 Archangel, and consider them to afford undoubted evidence that the 

 land, from the Vaga to Archangel, was a sea-bottom during the 

 period of existing species. A similar estuary appears to have existed 

 about 300 miles eastward, in the valley of the Petchora ; for Count 

 Keyserling found fragments of sea-shells, apparently of existing 

 arctic forms, at a distance of 180 miles from the present embouchure 

 of that river, strewed upon argillaceous slopes in the depression of 

 the valley. He further observed, that they do not occur in the ad- 

 joining plateaux ; and that these higher grounds are occupied by 

 sand, gravel and clay, containing here and there bones of the mam- 

 moth, from which he infers, that the shelly deposits were formed in 

 a bay of the sea that extended far into low lands, which were then 

 inhabited by great extinct mammalia. 



In the sketch given by the same authors of the structure of Si- 

 beria, they adduce a body of very satisfactory evidence to justify 

 the inference they draw, that the vast region in which the bones 

 of Mammoth, Rhinoceros and Bos Urus are so abundantly dis- 

 persed, and especially the wide and low tract of northern Siberia, 

 and all the low promontories between the Obe, tiie Yenessei and 

 the Lena, were elevated at a period long subsequent to the time 

 when large herds of these animals for many successive generations 

 inhabited that region. Following up the views first jiropoutided by 

 Mr. Lyell, to whom they do full justice, they infer that the change 

 of climate, the diminished temperature, occasioned by the increase 



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