37 



and its compound Mediterranean depression. Finally, he pointed 

 out that denudation and deposition were located by, and sub- 

 ordinated to, the actuating position of the dominant folds. 



He returned once again to the physics of the fold in his 

 Presidential Address to the Geological Society in 1903, where he 

 sums up his view of deformation as follows : Its type *" may 

 be that of undulation, warping, folding, gliding, fracture, or flow, 

 according as the magnitude of the stress, the speed of the action, 

 or the relative elasticity of the material may determine ; its 

 development may range in time from that of an instant to that 

 of an aeon ; and its extent from microscopic to hemispheric." 



2. Time Relations. 



In the address on ' The Face of the Earth/ Lapworth made 

 a brief allusion to the time-relation of folding as a key to f" the 

 cycles, systems and transgressions of the geological formations." 

 This idea he developed more fully in a communication to the 

 Geologists' Association on ' The Relief of the Globe/ in June, 1894, 

 which was never published. In this address, among other matters, 

 he showed how the succession of events revealed by the geological 

 Systems might be connected with the passage of waves each con- 

 sisting of a sagging arch and a buckled trough over the site of the 

 British Isles, thus connecting, as he loved to do, the events of the 

 past with the physiography of the present. 



3. The Dolomites. 



It may be mentioned that at the Edinburgh meeting (1892) of 

 the British Association at which Baron von Richthofen, the author 

 of the coral reef theory of the rock-masses of the Dolomites, was 

 present, he took the opportunity to expound the views to which 

 he had been led by the study of the literature of that region. He 

 had concluded that the remarkable and sudden local thickening 

 of the limestones was probably to be explained by folding and 

 earth movement, a view which has been entirely justified by the 

 work of Miss Ogilvie (Mrs. Ogilvie Gordon). J 



G. ECONOMIC AND ADVISORY WORK. 



Many phases of Lap worth's work show his voracity for exact 

 knowledge, which rarely left him satisfied until he had studied the 

 facts and sections for himself in the field. In nothing is this more 

 true than in his work on economic and expert lines ; and indeed 



* 63, p. 81. f 50, p. 617. 



I Quart. Journ. Geol. Soc., vol. xlix. (1893), pp. 1-78; id. vol. Iv. (1899), 



pp. 560-634. 



