410 A. Blytt on the probable Cause of 



are caused by lateral pressure, and that sncli lateral pressure is 

 sufficient to lift great chains of mountains into the air. But 

 Suess goes still further, for in a memoir, " Ueber die vermeint- 

 lichen sacularen Schwankungen einzelner Theile der Erdober- 

 flache " (in Verh. K. K. GeoL Beichs. 1880, pp. 171 et segq.) 

 he even denies any elevation by forces acting vertically from 

 below — neither mountain nor continent is elevated in this 

 manner. He says {I.e. p. 180) : — "There are no vertical 

 movements of the solid ground, with the exception of those 

 which proceed directly from the formation of folds. We 

 shall have to resolve to abandon the doctrine of the secular 

 oscillations of continents." 



A. de Lapparent, who sharply criticises Suess's theory of 

 "Horste " {Bull. Sac. GeoL France, ser. 3, tome xv. pp. 215 

 et seqq.), nevertheless agrees with him that the cooling of the 

 earth has formed great folds in the crust, and denies that any 

 elevations are not caused by foldings. Thus he says (/. c. 

 p. 21 7) : — " It is no longer necessary to oppose to the doctrine 

 of absolute elevations produced by forces acting directly from 

 below upwards, a protestation which has lost its object. For 

 the partizans of vertical impulsions are nowadays more than 

 scattered, and with the exception of a very few belated 

 persons no one would now venture to ascribe to such an 

 action an important part in the formation of mountains." 

 As he makes no limitation, it must be assumed that he will 

 not recognize any forces acting from below to elevate whole 

 land-masses. 



According to a statement of Suess's, in his Antl'dz der Erde 

 0885, Bd. i. p. 741), he seems to find an essential reason 

 for denying elevation by forces acting perpendicularly from 

 below in that w^e are quite ignorant of any force which could 

 be capable of causing such an elevation. 



The theories of Hutton and von Buch as to the action of 

 such forces seem therefore to be rejected by geologists of the 

 present day. Nevertheless there are still a few who hold 

 similar opinions. Thus J. C. Russel (U.S. Geol. Surv. 4th 

 Ann. Report, Washington, 1884, pp. 452, 453) says that the 

 fractures in " the Great Basin " are not in consequence of 

 any lateral pressure, but are caused by an extension in a 

 horizontal direction : — " The fractures are closely rciated to 

 an extension of the strata caused by upheaval." It seems to 

 me improbable that such a relation should be explicable by a 

 folding. C. E. Dutton also (U.S. Geol. Surv. 6th Ann. 

 Report, 1885, p. 198), at the same time that he recognizes that 

 many chains are folded by lateral pressure, says, M'ith regard 

 to the mountain-masses in Western North America : — ^' The 



