332 On the Geological Arrangement of Ancient Strata. 



and tertiary formations in the region of the Alps, and, indeed, in the 

 whole centre of the continent of Europe, implies a shallow state of the* 

 ancient seas there. The same appears to have been the case in the south 

 of England, while the sea would appear to have gradually deepened ta 

 the north-west of England, and continued deepening onwards through- 

 out Scotland. In South America, according to Elie de Beaumont, there 

 18 an entire absence of the oolitic series, while the gneiss, schistose, and 

 Silurian systems are extensively diffused. The chalk and tertiary strata 

 are also extensive, thus shewing a sea with deep and shallow bottoms, 

 but a deficiency of a middle level. It frequently occurs that some of 

 the higher formations, as the chalk or oolite, repose directly upon gneiss 

 or schistose strata ; this may arise from an elevation of these deeper 

 beds at once to the natural level of the higher strata, without affording 

 an opportunity for the formation of intermediate beds, orj, rather, a fit 

 locality for the peculiar animals which inhabit such. 



When any of the strata are thus raised above their appropriate levels, 

 it may be supposed that their inhabitants, or those of them that have 

 escaped destruction, immediately retire to lower levels. 



It is a circumstance frequently remarked by geologists, that fossil 

 remains, especially of fishes, are found only at particular points, as, for 

 instance, in a seam of shale of a few inches thick, while above this shale 

 many hundred feet of the same strata may exist without a trace of any 

 organism. This may indicate a convulsion of the oceanic bottom by 

 which myriads of fishes were entombed at once ; while, at the same time,^ 

 the stratum was depressed far below its proper level, by which means 

 the detritus afterwards deposited was at too great a depth to be tenanted 

 by living beings. Or the super-iinposed detritus may have been sud- 

 denly drifted and accumulated over the shale, without any great change 

 ©f level. This drifting by currents or convulsions of the ocean appears 

 to have been the cause of many of the vast accumulations of marine 

 sandstones which are not unfrequently visible ; and which, for many 

 hundred feet in depth, exhibit few or no traces of organised bodies ; and 

 even such as are found, consist only of the detached scales or bones of 

 fishes, as if the bodies to which they had belonged had been broken up 

 and destroyed by the violent action of the waters. 



Although depressions of strata may occasionally take place, yet it is 

 evident that such are of much less frequent occurrence than elevations, 

 because we very rarely, indeed, meet with a reversal of the order of 

 position which the labours of modern geologists have so successfully 

 established as generally, we may say almost universally, existing. In- 

 deed, it is astonishing to find with what accuracy fossil remains preserve 

 their respective positions in the earth's strata in every region of the globe 

 which has yet been explored by the geologist. Thus, the equivalents of 

 the British strata, containing almost identically the same fossils, have 

 t»een found on the continent of Europe, in Asia, in America, in the re- 



