572 KANSAS CITY REVIEW OF SCIENCE. 



It was during this long interval that all these organic forms were evolved 

 by natural selection. When asked why such must have been the case it is an- 

 swered that we must admit this explanation or we have no explanation; and 

 because it cannot be disproved, therefore it must be true. And this is called 

 science. There is abundant proof of the enormous lapse of time without resort- 

 ing to this manner of assuming that our ignorance is knowledge. Such a lapse 

 of time may have passed in this interval, but that such was the case is without 

 proof except as the evolution hypothesis is assumed as proof; but this itself is 

 sadly in need of proof. We pass over the next — Devonian — age with the single 

 remark that the rocks of this system, containing the fossil forms of numerous 

 species of organic forms, especially fishes, give proof that long ages must have 

 elapsed during their deposition. 



W^e next come to the carboniferous age — age of acrogens or coal age. 

 Here we find the most indisputable evidence of enormous stretches of time. 

 The foot-prints of time are so indelibly impressed on the rocks of this age, 

 that in some places some approximation to a calculation mf-y be made. The 

 thickness of the rocks of this system vary from 9,000 feet to 15,000 feet. The 

 coal-measures proper vary between 4,500 and 13,000 feet. We here have 

 the most irrefragible proofs of the frequent oscillation of the earth's crust. The 

 seams of coal, which compose but a small portion of the thickness of these 

 rocks, are interstratified with the various strata of sandstones, shale, and lime- 

 stone composing this formatior. 



As coal is the product of vegetation, which must have grown at the sur- 

 face, it is evident that to form the seams of coal found at various depths would 

 require that each of these various horizons should have been at the surface at 

 the time when the material forming the coal was accumulated. Now, we find 

 in different coal-fields considerable numbers of these seams separated by inter- 

 vening strata of rock. Thus in Nova Scotia there are 81 ; in Wales 100 ; in Bel- 

 gium 100; in Westphalia 117. These aggregate, in some cases, as much as 15a 

 feet of coal that would be passed through in sinking a shaft from the surface to 

 the lowest coal-seam. It is evident that where these different seams are found, 

 the land has been elevated and depressed at least once for each of the seams 

 found. 



There would be a long period when the land surface was above the water \ 

 immense forests of vegetation would flourish until a huge layer of it was accu- 

 mulated, when by some convulsion of the crust of the earth, or by a gentle — 

 perhaps to human eyes it would have been imperceptible — subsidence, it would 

 be depressed below the waves and receive, either from fluviatile or marine sedi- 

 ment, a layer of earthy material, covering the layer of organic matter to a depth 

 of many feet. A reversal of the process by which the land was depressed, 

 again elevates the surface above the waters, and again a layer of vegetation 

 would be produced, to be in turn buried as the former was. And thus these 

 alternate elevations and depressions continued till, as we have seen in some 

 cases, an hundred or more beds of vegetable matter have successively grown 



