ss^ 



ILLUSTRATIONS OF THE 



Hadriatlc 

 that a fim 



We may colled from Guettard 



grad 



is found 



gravel 



and earth which cover the great plain of Poland 

 from Mount Krapack to the Baltic f . The rea- 

 fon of this gradation is evident j the farther the 

 Hones 



r 



they h 



have travelled, and th 



more 



d 



th 



rubbing 

 fmaller they grow, the 

 more regular is the figure they affume, and the 

 greater the quantity of that finer detritus which 

 conflitutes the foil. The walhing of the rains 

 and rivers is here obvious ; and each of the 

 three quantities juft mentioned, if not directly 

 proportional to the diftance w^hich the Hones 

 have migrated from their native place, may be 

 faid, in the language of geometry, to be at leaft 

 proportional to a certain fundion of that diltance. 

 343. The immenfe quantity o£ cuilloitx ronUs^ 

 or rounded gravel, colleded in the immediate vi- 

 cinity of mountainous tradts, has led fome geo- 

 logifts to fuppofe the exiftence of ancient cur- 

 rents, W'hich defcended from the mountains, in 

 a quantity, and with a momenhim^ of which there 

 is no example in the prefent ftate of the world. 

 Thus SaulTure imagines, that the hill of Su- 

 pergue, near I'uiin, which is formed of gravel, 

 can only be explained by fuppofing fuch cur- 

 rents 



* Voyages aux Alpes, torn. iii. § 13 £5- 



f Mem, Acad, des Sciences, 1762, p. 234 ; 293, &c. 



