GEOLOGY. 



METAMORPHISM. 



MR. J. GEIKIE, in the "Proceedings of the Geological Society," 

 communicates a paper ' ' On the Metamorphic Lower Silurian 

 Rocks of Carrick, Ayrshire," which furnishes important evidence 

 in support of the omnion that metamorphisin is due to hydrother- 

 mal action. In his opinion, the examination seems to prove: 1. 

 That the strata (felspathic, dioritic, serpentinous, and calcareous 

 rocks) owe their metamorphism to hydrothermal action. 2. That 

 the varying mineralogical character of the rocks is due principally 

 to original differences of chemical composition, and not to infiltra- 

 tion of foreign matter at the time of metamorphism. 3. That the 

 highly alkaline portions of the strata have been most susceptible 

 of change. 4. That in beds having the same composition, but 

 exhibiting various degrees of alteration, the intensity of the met- 

 amorphism has been in direct proportion to the amount of water 

 passing through the strata. 5. That in some places the rocks 

 have been reduced to a softened or pasty condition. 



ANTIQUITY OF LIFE UPON THE EARTH. 



At the annual meeting of the Swedish Academy of Science, M. 

 Nordenskiold announced that a discovery of great importance to 

 geological science had been made in the hill of Nullaberg, Swe- 

 den. A large deposit of bituminous gneiss, 33 metres in thick- 

 ness, has been found imbedded in layers of gneiss and mica schist. 

 It is composed, in addition to felspar, quartz, and mica, of a black, 

 coal-like substance, containing carbon and hydrogen, in fact, a 

 real organic substance, formed of the remains of plants or ani- 

 mals coeval with the deposit. He added that there could be no 

 doubt as to the antiquity and geological situation of the strata of 

 Nullaberg ; infiltration was impossible. The inference was that 

 the crystalline stratified rocks of Scandinavia were formed when 

 there existed animated creatures, but at a long time anterior to 

 the period when life is supposed to have first existed on the earth. 



PRIMITIVE CLIMATE OF THE EARTH. 



The primitive atmosphere of the earth was greatly richer in 

 carbonic acid than the present, and therefore unfit for the respira- 

 tion of the warm-blooded animals. The agency of plants in 

 purifying this atmosphere was long ago pointed out, and the great 



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