part 1] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. ix 



the other the links have a limited possibility of variation in length, 

 representing a condition where the rigidity of the crust is given a 

 certain possibility of influence on the resulting elevation of the 

 surface. On giving differences in height to the elevating blocks, 

 to represent the varying amount of uplifting force supposed to 

 exist under the mountain-range, it is found that the two strips do 

 not run at the same level, but the second runs alternately higher 

 and lower than the first, just as geodetic measurements have shown 

 is the case in the great ranges of mountains. The model is of no 

 value as evidence in favour of the hypothesis which it was designed 

 to illustrate, but is regarded as of some interest in visualizing the 

 consequences of an hypothesis which seems worthy of closer in- 

 vestigation than it has yet received. 



February 4-th, 1920. 



Mr. G. W. Lamplugh, F.R.S., President, 

 in the Chair. 



Francis Alleyne Marr, D.S.O., Geologist to the Burma Oil Com- 

 pany, c/o Messrs. Scott & Co., Rangoon (Burma) ; and the Rev. 

 Benjamin Oriel, B.A., B.Sc, 26 Parkside, Eltham, S.E. 9, were 

 elected Fellows of the Society. 



The List of Donations to the Library was read. 



The following communication was read: — 



' Geological Sections through the Andes of Peru and Bolivia : 

 II — From the Port of Mollendo to the Inambari River.' By 

 James Archibald Douglas, M.A., B.Sc, F.G.S. 



Rock-specimens and lantern -slides were exhibited by Mr. J. A. 

 Douglas, in illustration of his paper. 



Flints showing artificially -made bulbs of percussion were 

 exhibited by Dr. John Switzer Owens, F.G.S. 



