256 ON ™ E DECLIVITIES OF MOUNTAINS, 



XIII. 



An Effay on the Declivities of Mountains. By Richard 

 Kirwan, Efq. L. L. D. F. R. S. and P. R. I. A, 



Introductory re- AMONG the various caufes to whofe activity the planet we 

 marks * inhabit owes its prefent wonderfully diverfified appearance, 



fome undoubtedly exerted their influence from its very origin, 

 and others at fubfequent periods ; of thefe lad one at leaft, 

 namely, the Noachian deluge, was univerfal in its operation, 

 while the effects of many more were partial and local, fuch as 

 thofe refulting from earthquakes, volcanos, particular inunda- 

 tions, &c. 



In a general furvey of the globe, it is only to general caufes, 

 whofe operation was univerfal, that our attention can be di- 

 rected ; the effects of partial caufes being the proper objects of 

 the geological hiftory of thofe countries that were particularly 

 affected by them. 



But to diftinguifli caufes of the former clafs from thofe 

 whofe operation was more confined, it is neceflary to difcover 

 , fome character by which their effects may unequivocally be 

 difcerned. 



Now a general uniformity, or agreement in fome particular 



circumftance in every part of the globe, feems to be a fure teft 



of the operation of fome general caufe. The difcovery of 



uniform appearances is therefore of primary importance in 



geological refearches. In the prefent effay I mail confine my- 



felf to the inveftigation of one inftance of this fort, namely, the 



inequality of declivity which the fides or flanks of mountains 



exhibit in every part of the globe hitherto examined according 



to the points of the compafs to which they faqe, and are ex- 



pofed. 7 



AH high movm- That one part of almoft every high mountain or hill is Keeper 



tains or hills th an another, could not have efcaped the notice of any perfon 



much fteeper wno na d traverfed fuch mountains ; but that Nature in the for- 



thaa the other. ma tion of fuch declivities had any regard to different afpects of 



points of the compafs, feems to have been firft remarked by the 



celebrated Swedifh geologift Mr. Tilas, in the 22d vol. of the 



Memoirs 



