74 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



berg, Bailey, and others, it was then known that from deposits, 

 chiefly of the siliceous cases of plants of the lowest order, 

 the diatomaceae, a "cap" of siliceous sand was being formed 

 at the northern, and another at the southern pole. It was 

 also proved that the grand areas of the general sea-bottom 

 of the Atlantic and Pacific oceans were similarly constituted 

 of a girdle of calcareous mud, of indefinite depth, formed by 

 a similar vein of discarded calcareous shells of animals of low 

 organization the foraminifera. Now this white calcareous 

 matter of the foraminifera shells has been shown by the Chal- 

 lenger researches to be replaced, in certain deep oceanic val- 

 leys between Tristan d'Acunha and Kerguelen's Island, and 

 elsewhere, by a very fine red clay. In certain geological 

 deposits, of greater or less antiquity, beds of glauconite, or 

 green siliceous sand, exist, which are composed entirely of 

 the casts of ancient foraminifera formed of a green material, 

 which is a compound of silicate of iron and alumina. The 

 chemist of the Challenger having found that, from the decom- 

 position by weak acids of the calcareous shells dredged up 

 from the 18,000-feet depths, there is a residuum of one or two 

 per cent, of red marl, exactly like that dredged up from the 

 18,000-feet depths of the valleys referred to, the conclusion 

 is arrived at that the red mud is the accumulation of this 

 small percentage of clayey matter, resulting from the whole- 

 sale decomposition of the calcareous polythalamous shells. 

 The novelty of the Challenger discovery consists, therefore, 

 in the fact that clay deposits can also be assigned, like sili- 

 ceous and calcareous deposits, to the resultant debris of organ- 

 isms living at the surface of the sea. Supposing, therefore, 

 that the whole globe were immersed under an entire envel- 

 ope of water, deposits of all the materials of our stratified 

 geological rocks could be going on without the slightest as- 

 sistance from the degradation and wearing away of any actual 

 land surface at all ; and these deposits, subjected in the or- 

 dinary natural course of events to ordinary processes and 

 actions, could be modified into gneiss, schists, slate, limestone, 

 and every variety of geologic rocks. 3 A, Jem. 6, 1875, 171. 



INFLUENCE OF FORESTS ON CLIMATE. 



Clare, in the Revue des Deux Mondes, takes strong ground 

 as to the exercise by forests of a very decided influence upon 



