358 Sir H. H. Howorth — Geological History of the Baltic. 



present broken condition, and this, not in Tertiary times, but just at 

 the threshold of the current geological period. 



In order to set out the reasons for this important and really far- 

 reaching induction I must be allowed to make some preliminary 

 remarks on what may seem to be unnecessary to those who have not 

 measured, as I have done, the vis inertice of the older type of 

 geological mind which still survives among certain veterans of the 

 science. 



There was a time when the various movements of the earth's crust 

 (of which the evidence is patent enough) were attributed to the 

 operations of some unknown but postulated subterranean energy which 

 was supposed to be able (in limited areas) to lift up by forces acting 

 perpendicularly or to let down by similar impulses great masses of the 

 earth's strata, and thus to largely cause the diversified features of 

 the earth's crust. This view is now only held by a small and 

 shrinking body of geologists. The great mass of them who have 

 surveyed geological problems on a continental scale and realized how 

 far-reaching the phenomena must in some cases have been, have found 

 it impossible to maintain an hypothesis which will not meet the facts 

 as we now know them. The more influential of the modern teachers 

 of the science are no longer satisfied, like the extreme glacialists are, 

 to rely upon causes for which no adequate physical justification has 

 ever been produced, and which necessitate the postulating of qualities 

 and characteristics in the materials which build up the earth's solid 

 envelope which refuse to be verified by experiment. These newer 

 men who recognize that geology must in the long run rely upon 

 physics to supply it with a workable platform have found a perfectly 

 satisfactory reason for earth movements on a very big scale and over 

 very large areas. The postulate they stand upon in this matter is, 

 that the earth is inevitably losing its heat by radiation and in the 

 process is shrinking, and in shrinking it has to compel its upper 

 strata to accommodate themselves to a smaller space. The result is 

 great lateral (and not perpendicular) thrusts which have squeezed 

 the beds into wave-like and sinuous curves and ribbons, with 

 alternating anticlinal and synclinal folds. 



On this point let me quote two excellent authorities, and as tliere 

 must be no quarrel about their meaning I will quote their actual 

 words :— 



Suess says definitely: " Es giebt keinerlei verticale Bewegungen 

 des Festen, mit Ausnahme jener, welche etwa mittelbar aus der Falten 

 bildung hervorgehen. Die Felsarten der Erde besitzen in keinerlei 

 Gestalt jene rathselhafte elevatorische kraft welche man ihnen in 

 einer Zeitlnzuschreiben geneigt, und vielleichtbis zu einem gewissen 

 Grade berschtigt war, im welcher. . . . Wir werden unsenschliessen 

 miissen letzte Form der Erhebungstheorie die Doctrin von den Saecu- 

 laren Schwankungen den Continent zu verlassen." Heim urged the 

 same view (Jahrbuch k.k. Geol. Reichsanst Wien, 1880, p. 180). 



Lapparent is still more positive. He says : "II ne s'agit pas 

 d'avantage d'opposer a la doctrine des soulevements absolus 

 produits par des forces qui agiraient directement de has en haut, 

 nne protestation devenue sans objet. Car les partisans des impulsions 



