Notices of Memoirs — Photographs of Geological Interest. 517 



for a few inches into the sands, as was seen in the recently widened 

 railway cutting at Redhill and in the pit-sections at the Dover 

 Collier3^ Similar effects have often been supposed to denote the 

 breaking up of the surface below the junction by erosive agencies, 

 but this explanation is rarely adequate. 



While some of these local disturbances may have bee« caused 

 by unequal loading within limited basins of sedimentation, in the 

 jnatter discussed by E. Re3'er,^ the author is of opinion that in most 

 cases they may be assigned to local stresses resulting in part from 

 the differential contraction of sediments of diverse composition 

 while losing their water of sedimentation, and in part from their 

 unequal yielding under equal superincumbent load. Masses of peat, 

 sand, clay, and calcareous sediments accumulated under normal 

 conditions must pass from the wet state to the consolidated or partly 

 consolidated state with different time - rates and with different 

 physical results ; and we may expect to find signs of local tension 

 and readjustment along the boundaries of such masses. 



In thick wedges of strata which thin out rapidly, as, for example, 

 in the Triassic rocks of many localities and the Wealden and Lower 

 Greensand of the south of England, differential shrinkage may be 

 responsible for many of the smaller vertical displacements by which, 

 the beds are readjusted. Faults are sometimes found to dwindle 

 and die out downward, and in certain cases these may be explicable 

 as the result of unequal contraction in masses of irregular thickness. 



IX. — Photographs of Geological Interest in the United 

 Kingdom.- Fourteenth Report of the Committee : 



Consisting of Professor James Geikie (Chairman), Professor W. W. Watts 

 (Secretary), Professor T. G. Bouney, Professor E. J. Garwood, Professor S. H. 

 Eeynolds, Dr. Tempest Anderson, Mr. Godfrey Bingley, Mr. H. Coates, 

 Mr. A. K. Coomaraswamy, Mr. C. V. Crook, Mr. J. G. Goodchild, Mr. WilHam 

 Gray, Mr. Robert Kidston, Mr. J. St. J. Phillips, Mr. A. S. Eeid, Mr. J. J. H. 

 Teall, Mr. P. Welch, and Mr. H. B. Woodward. 



friHE Committee have to report that during the year 463 new 

 X photographs have been received, bringing the total number in 

 the collection to 3,771. This exceeds by 50 the largest number of 

 new photographs previously recorded in a single year, and the yearly 

 average now reaches 268. About 60 additional photographs have 

 been sent in since this report was written. 



The usual geographical scheme is appended. Brecknock, Car- 

 digan, Nairn, and Ross appear for the first time, and very sub- 

 stantial additions are made to Cheshire, Dorset, Norfolk, Yorkshire, 

 Glamorgan, the Channel Islands and Scilly, Inverness, Sutherland, 

 Antrim, and Louth. The following twenty-five counties are still 

 entirely unrepresented : — Cambridge, Huntingdon, Rutland, Car- 

 marthen, Clackmannan, Dumbarton, Dumfries, Kincardine, Kinross, 

 Roxburgh, Selkirk, Carlow, Kildare, Kilkenny, King's County, 



1 K.K. Geol. Eeichsanstalt Wien, Jahrbuch, xxxl (1881), pp. 431-444. 

 ^ Abstract of paper read before the British Association, Southport, Section C 

 (Geology), September, 1903. 



