Dr BoutTs Geological Observations. 8S 



not natural to suppose that an arenaceous or calcareous forma- 

 tion should present differences in different countries, or on 

 the opposite sides of a basin, or in the intermediate points be- 

 tween the two sides of a basin. If these deposits are the 

 products of sea and river alluvium, it is evident that the nature 

 of the debris will vary according to the localities, and that their 

 quantity will be more or less great ; which would also partly be 

 the case, should these rocks be attributed to a chemical precipi- 

 tation. If the observed deposits are nothing else than the re- 

 mains of marine animals, or similar productions, taken up and 

 arranged by the sea-water, the same bed will present, in diffe- 

 rent localities, varieties not only in the nature of the rock, but 

 also in the Jbssils ; for marine animals are not the same at 

 different depths of the sea, at different distances from the coast, 

 or under different zones, or in different places of the world ; and 

 their debris must also be variously arranged or grouped toge- 

 ther by the sea, according to the unequal motions and bottom 

 of the ocean. For farther elucidations of this subject, I may 

 refer the reader to the late excellent Memoir of M. C. Prevost. 

 On the other hand, there are mineral masses, which are gene- 

 rally distributed, as sandstones, &c. ; while others are much 

 more local, as all unstratified rocks, also limestones, gypsum, 

 salt, and coal. The unstratified rocks seem to have given rise 

 to certain deposits in the countries where these rocks have ap- 

 peared ; thus the granite rocks are accompanied with certain 

 conglomerates, the serpentines are near certain sandstones, the 

 porphyries occur in the neighbourhood of the coal-formation, 

 and of various flcetz sandstones, the basalts are associated with 

 deposits of lignite and arenaceous rocks, &c. It should not 

 then excite surprise to find differences in the beds of the same 

 formation in different countries. In this manner, the transition, 

 or floetz sandstones of a country, which contain no unstratified 

 rocks, will differ a little from those of another country, in which 

 these igneous, or unstratified rocks, are present. It is acknow- 

 ledged that limestone rocks are not equally distributed over the 

 earth'*s surface, but that they have been formed in particular lo- 

 calities, as in basins, sinuosities of a basin, or along submarine 

 rocky chains. The gypsum and salt also evidently belong to 

 the local deposits, if their mixed igneous and aqueous origin be 



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