504 



GEOLOGY. 



When the beds inchne in a single direction, they form a monocline. 

 When beds are arched so as to incHne away from one another, they form 

 an up-fold or anticline (Figs. 388 to 391). The antichne may depart from 



Fig. 393.- -Isocline, (Van Hise, U. S. Geol. Surv.) 



Fig. 394. — Anticlinorium : diagrammatic. (Van Hise, U. S. Geol. Surv.) 





Fig. 395. — Anticlinorium. General section in the central massif of the Alps. 



(Heim.) 



its simple form, as shown in Figs. 390 and 391. When beds are curved 

 downward so as to incline towards one another, they form a syncline 

 (Fig. 392). When beds assume the position shown in Fig. 393, the 

 folds are said to be isoclinal. When they are arched so as to form a 

 cone or dome, and incline in all directions from a central point, they 

 are said to have a quaquaversal dip. When considerable tracts are 



