GEOLOGY. 301 



which I consider to be wholly incompatible with the data in our possession, 

 and at variance with the laws of isothermal lines. 



If, however, we adopt the theory of a former submarine drift,* followed 

 by a subsequent elevation of the sea-bottom, as easily accounting for all the 

 phenomena, we may explain the curious case brought to our notice by Sir 

 Edward Belcher, by supposing that the tree he uncovered had been floated 

 away with its roots downwards, accompanied by attached and entangled 

 mud and stones, and lodged in a bay, like certain "snags" of the great 

 American rivers. Under this view, the case referred to must be considered 

 as a mere exception, whilst the general inference we naturally draw is, that 

 the vast quantities of broken recent timber, as observed by numerous Arctic 

 explorers, were drifted to their present position when the islands of the 

 Arctic Archipelago were submerged. This inference is indeed supported by 

 the unanswerable evidence of the submarine associates of the timber: for, 

 from the summit of Coxcomb Range in Banks Land, and at a height of 500 

 feet above the sea, Capt. M'Clure brought home ' a fine large specimen of 

 Cyprina Islandica, which is undistinguishable from the species so common in 

 the glacial drift of the Clyde ; whilst Capt. Sir E. Belcher found the remains 

 of whales on lands of considerable altitude in lat. 78 north. 



Reasoning from such facts, all geologists are agreed in considering the 

 shingle, mud, gravel, and beaches in which animals of the Arctic region are 

 imbedded hi many parts of Northern Europe, as decisive proofs of a period 

 when a glacial sea covered large portions of such lands ; and the only dis- 

 tinction between such deposits in Britain and those which were formed in the 

 Arctic Circle is, that the wood which was transported to the latter has been 

 preserved in its ligneous state for thousands of years, through the excessive 

 cold of the region. 



OX THE GROWTH OF STALACTITES. 



Professor "W. B. Rogers, at a late meeting of the Boston Society of Natural 

 History, gave the following brief sketch of facts which he had observed in the 

 growth of stalactites : 



A drop of water, charged with carbonate of lime, is seen to form at a parti- 

 cular point of the roof, and after its descent, another drop, by the same 

 mechanical causes, takes its place. It is not necessary to suppose a hole 

 around which the concretion may collect. Usually there is none. At the 

 margin of the drop where it thins away to a film, evaporation and the loss of 

 carbonic acid combine to cause a precipitation of part of the dissolved car- 

 bonate, which, on separating, attaches itself to the rock in the form of a very 

 delicate white ring, corresponding to the margin of the liquid. Each succeed- 

 ing drop deposits a similar ring in contact with and beneath that already 

 formed, until the whole is prolonged downwards in the shape of a quill-like 



* Dr. Hooker informs me that all the specimens sent to him were collected in mounds 

 of silt, rising up from the level of the sea to 100 feet or more above it ; and he entirely 

 coincides with me in the belief that the whole of this timber was drifted to the spots 

 where it now lies. 



