On the Declivities of Mo7inial.nL 35 



Hence, 6°, low granitic or other primitive hills are fre- 

 quently uncovered by adventitious ftrata on all fides, as at 

 Phanct in the county of Donegal, or are covered on all fides; 

 the impregnated waters either eafily parting over them, or 

 Stagnating upon them, according to the greater or leffer ra- 

 pidity of its courfe, and the obftacles it met with. 



The two-fold motion of the antient ocean is noticed both 

 by Burton and Bergman, but neither of them has deduced 

 from it the true explanation of the phenomena of which we 

 here treat. Buffon attributes the formation of fecondary 

 mountains to depofition or fediments from the fea after the 

 exiftence of fiili, i Epoques, p. 143, in 8vo., which, he fays, 

 inverted the bales of mountains, without noticing any diflinc- 

 tion of fides, p. 144 and 170. He thinks thefe fediments 

 were equally conveyed from both poles towards the equator; 

 for it is in the equatorial regions that, he thinks, thofe miohty 

 caverns opened, towards which the primitive ocean was im- 

 petuously borne, and in which it was ingulphed ; p. 181, 

 182, and 183. If fo, fimilar declivities fliould be formed on 

 the fouthern as on the northern fides of mountains; which is- 

 contrary to the obferved fails. His explanation of the eaftern 

 and wcllern declivities is defective and erroneous; for he at- 

 tributes the.abruptnefs of the weftern fides to the erofion of 

 the coafts on that fide (an erofion that exifts onlv in fancy), 

 and the fmoothnefs of the eaftern, to the gradual defertion 

 and retreat of the fea on that fide, p. 184 and 185 ; a retreat 

 equally fictitious, as De Luc has well fhown. Whereas, 

 fincc the general motion of the fea is from eaft to weft, if 

 the erofion were of either fide, it fliould rather be on the 

 eaftern than on the weftern ; befides, if the gentle declivities 

 of the eaftern fides of mountains arofe from the gradual re- 

 treat of the fea, the petrifactions of the fecondary mountains 

 thus formed fliould court ft of fuch fliell-fifh as inhabit find- 

 low feas or fhorcs, whereas they confift chiefly of thofe called 

 ,-r, which inhabit the greater! depths*. 



With refpeel to the eaftern and weftern declivities, Mr. 

 Bergman's account of the origin of their inequality agrees 

 ly with mine, 2 Bergm. Erdeklotet, § 183 and 187; 

 ■• r Bcrgm. Erdekugel, p. 31c. 



