f 54 Hints for the Formation of 



tain, the chain of which it makes a part, and the adjacent 

 valleys. 



8. To examine alfo whether the declivity of the ftrata \i 

 conformable to that of the external furface of the mountain; 

 that is to fay, whether they defcend towards the outride of 

 the mountain, or towards the interior part. 



9. To examine next whether the inclination is the fame 

 from the bottom of the mountain to the fummit, or whether 

 it varies at different heights; whether it be the fame or dif- 

 ferent at the. oppofite fides of i\\z fame mountain. Strata in 

 the form of a fan *. 



10. It is of importance to obferve, in inclined or vertical 

 ftrata, whether their thicknefs is not greater at their baiis 

 than at their fummit. 



11. To obferve the joinings of the (Irata, and whether any 

 fubftance different from that of the ftrata i3 placed be- 

 tween them, and what is the nature and thicknefs of this 

 fubftance. 



13. To obferve whether the contiguous or correfponding 

 joinings ofthefe ftrata are fmooth or unequal; whether there 

 areobferved in them any knots that exhibit traces of cryftal- 

 lifation or undulations proceeding in a certain direction. 



13. In mountains confifting of ftrata different in their na- 

 ture, or of different thicknefs, to obferve whether their re- 

 turn is periodical, fo that the fame order recommences after 

 a certain number or determined interval. 



14. Whether, at the bottom of a mountain confifting of 

 horizontal ftrata, there are not found mountains compofed of 

 vertical ftrata reft ins ascainft the baiis of that mountain. 



15. In bent or circular ftrata, to obferve in the elbows or 

 points where the flexion is greateft, whether the ftrata are or 

 are not broken, 



16. When the ftrata have the form of a C, to obferve whe- 

 ther at the back of the C there is not a vacuity, which proves 

 that the upper part has been thrown above the under part. 



* Voyage i dans les Alpes. § 656 and 677. 



17- T<* 



