JURA. GEOLOGY. 207 



of the parts which he has marked for inquiry, those 

 details of which he is generally enabled by this method 

 to form a rational conjecture. 



From the top of Ben shianta the stratification of Jura 

 is exhibited in great beauty, and with a striking magni- 

 ficence of natural perspective ; presenting a scene of un- 

 common grandeur and effect. The general inclination 

 of the beds is even and regular, while they rise from 

 the eastward and are abruptly broken off towards the 

 west. Hence, wherever they form hills, a continued 

 range of their edges is seen, extending in a constant 

 but interrupted succession till they vanish beyond the 

 point of distinct vision. Thus they become all mar- 

 shalled in straight lines, which, tending from several 

 parts to the vanishing point, give the appearance of regu- 

 lar lines drawn by the hand of a painter ; the breaks 

 and interruptions disappearing in the general regularity 

 of the whole. 



Notwithstanding the apparent regularity of the dip of 

 these strata, there are anomalies in it in various places. 

 When the minute details of the angles of elevation are 

 examined, it will be seen that they are not precisely 

 the same every where, and that the strata consequently 

 lie in an undulating plane. These irregularities are 

 however neither considerable nor frequent ; although 

 they are such as to render it impossible to assign the 

 precise elevation of the strata. Such an attempt is 

 often indeed no less fruitless than difficult, as but little 

 advantage can arise from a minuteness of detail in this 

 respect. Ben shianta seems to afford a medium standard 

 quantity ; the angle of inclination being here twenty- 

 seven degrees, and the dip, as nearly as I could ascertain 

 it by the magnet, to the E. S. E . ; the variation being 

 taken at 26. The direction of the strata in this mountain 

 is therefore north north east. But from the occasional 

 undulation of the lines of bearing visible in other parts 

 of Jura, it is scarcely possible to assign the exact linear 



