INORGANIC GEOLOGICAL DYNAMICS. 553 



elevated beds of coral, which, occurring in other places, indicate a 

 recent rising of the land ; and on such grounds as these he divides 

 the surface of those parts of the ocean into regions of elevation and 

 of depression. 



The labors of coralline zoophytes, as thus observed, form masses of 

 coral, such as are found fossilized in the strata of the earth. But our 

 knowledge of the laws of life which have probably affected the distri- 

 bution of marine remains in strata, has received other very striking 

 accessions by the labors of Prof. Edward Forbes in observing the 

 marine animals of the ^Egean Sea. He found that,, even in their 

 living state, the mollusks and zoophytes are already distributed into 

 strata. Dividing the depth into eight regions, from 2 to 230 fathoms, 

 he found that each region had its peculiar inhabitants, which disap- 

 peared speedily either in ascending or in descending. The zero 

 of animal life appeared to occur at about 300 fathoms. This curious 

 result bears in various ways upon geology. Mr. Forbes himself has 

 given an example of the mode in which it may be applied, by deter- 

 mining the depth at which the submarine eruption took place which 

 produced the volcanic isle of Neokaimeni in 1707. By an examina- 

 tion of the fossils embedded in the pumice, he showed that it came 

 from the fourth region. 5 



To the modes in which organized beings operate in producing the 

 materials of the earth, we must add those pointed out by the extra- 

 ordinary microscopic discoveries of Professor Ehrenberg. It appears 

 that whole beds of earthy matter consist of the cases of certain infu- 

 soria, the remains of these creatures being accumulated in numbers 

 which it confounds our thoughts to contemplate.] 



Speculations concerning the causes of volcanoes and earthquakes, 

 and of the rising and sinking of land, are a highly important portion 

 of this science, at least as far as the calculation of the possible results 

 of definite causes is concerned. But the various hypotheses which 

 have been propounded on this subject can hardly be considered as 

 sufficiently matured for such calculation. A mass of matter in a state 

 of igneous fusion, .extending to the centre of the earth, even if we 

 make such an hypothesis, requires some additional cause to produce 

 eruption. The supposition that this fire may be produced by intense- 

 chemical action^between combining elements, requires further, not only 

 some agency to bring together such elements, but some reason why 



Brit sh Assoc. Reports, 1 843, p. 177. 



