(54 UPHEAVAL AND SUBSIDENCE. 



1^1 



pell-mell, more or less bituminous and preserving their tissue, found acci. 

 dentally buried in the midst of sedimentary deposits, and which probably 

 had a similar origin to those transported by great rivers, which are deposited 

 in lakes or conveyed to the middle of seas. 



Remains of shells are rare in deposits of coal, properly so called. There 

 is no trace of them in any of the deposits of the centre of France ; and it 

 is only in the great formation comprising the north of France, Belgium, 

 and England, that some examples are met: marine shells are found in the 

 environs of Liege and of Namur, in Derbyshire, &c. Fresh-water shells, 

 similar to u'nio and anodo'nta, are found in the same place. In most depo- 

 sits of lignite, in which the structure of the wood has generally disappeared, 

 we find, on the contrary, a great number of fluviatile shells, which proves, 

 that the formation of these deposits took place in fresh-water lakes. 



EFFECTS ATTRIBUTABLE TO UPHEAVAL AND SUBSIDENCE. 



7. At whatever height we may find fluviatile deposits on the 

 surface of the globe, there is nothing to excite astonishment; for 

 we readily conceive that lakes could have existed at all heights on 

 continents, and that after their waters flowed away their deposits 

 remained dry on the soil. But we find also marine deposits at all 

 heights, in very extensive beds, and at first sight it is not so easy to 

 account for them. It is evident that such deposits could have been 

 formed only under waters of the sea ; and, as they are now found 

 thousands of yards above the present level of the ocean, we must 

 admit one of two things; either that the water was elevated above 

 these points for a sufficiently long time to form thick beds there, 

 or that these deposits were raised up from the bottom of the sea to 

 the height we now find them. Nothing in the phenomena of the 

 present time warrants a belief, that the sea, which has not changed 

 its level within the time of history, could have been so elevated, 

 long enough to form considerable deposits. The universal deluge 

 of the Holy Scriptures was a catastrophe of short duration, and 

 therefore could not have produced the immense deposits referred 

 to, which, everything leads us to believe, were formed slowly. 

 Besides, this catastrophe is comparatively of modern date, and 

 must be referred to the last modification of the surface ; now, all 

 the deposits of shells of which we speak were long anterior, and 

 were independent of facts belonging to the history of the human 

 race. Nothing informs us what became of the excess of water (a 

 greater or less volume than now exists) above the present level, 

 without having recourse to divine interference, which must have 

 been frequent in ancient times, to cause these waters to appear or 

 disappear a great many times, and even suspend the action of the 

 laws of equilibrium. In fact, very often deposits of shells, seen 

 here and there at a great height, are not found on corresponding 

 summits, and are represented on the contrary with all their charac- 

 ters, thousands of yards lower down ; hence we must suppose the 



7 How is the presence of marine shells in deposits, at great height* 

 nboye the presen* level of the sea, accounted for ? 



