THE SURFACE OF THE GLOBE. 67 



in the neighbourhood of Paris ; but there is no bone of a terrestrial 

 mammiferous animal. 



In spite of the most indefatigable researches, I have found it im- 

 possible to discover any distinct trace of this class prior to the layers 

 deposited on the coarser limestone : lignites and molasses certainly 

 have them; but I much doubt whether these earths are, as is be- 

 fievedj anterior to the limestone ; the places where they have furnished 

 bones are too limited and too few, therefore we may suppose there 

 has been some irregularity or some recurrence in their formation. 

 On the contrary, when we reach the deposites immediately above the 

 limestones, the bones of terrestrial animals appear in great numbers. 



Thus, as it is rational to believe that shells and fishes did not exist 

 at the period of the formation of the primordial layers, so may we also 

 believe that the oviparous quadrupeds began with fishes and the first 

 production of secondary formations ; but that terrestrial quadrupeds 

 did not appear, at least in considerable numbers, until a long time 

 afterwards, and when the thick limestone which now contains the 

 greatest portion of our genera of shells, although different in species, 

 had been deposited. 



We must remark, that these coarse limestone strata, which we make 

 use of in Paris for building, are the last banks which denote a long 

 and peaceful flowing of the sea over our own continents. After them 

 we find layers filled with shells and other marine productions ; but 

 these consist of shifting layers, sands, marls, sand-stones, and soft 

 clays, which rather denote changes more or less sudden than a quiet 

 settling ; and, if there be any stony or regular banks of any size be- 

 neath or above these moving layers, they generally betray marks of 

 having been deposited from fresh water. 



Nearly all the known bones of viviparous quadrupeds are then either 

 in these deposites of fresh water, or in the alluvial deposites ; and con- 

 sequently, there is reason to believe that these quadrupeds had not 

 begun to exist, or at least to leave their relics in the layers that we 

 are able to fathom, till after the last retreat but one of the sea, and 

 during that state of things which had preceded its last irruption. 



But there is also an order in the arrangement of these bones amongst 

 themselves ; and this order bespeaks a very remarkable succession in 

 their species. 



First, all the unknown genera, the palseotheria, the anoplotheria, 

 &c, on the relative situation of which we have certain ideas, belong 

 to the oldest of the layers in question ; to those which rest imme- 

 diately above the coarse limestone. It is these, principally, which fill 

 the regular banks, deposited by soft waters or certain shifting beds, 



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