731; : REPORT— 1900. 



water currents by a rocky ridge called EDglish Stones on the seaward side of ttetn, 

 are finely ridged. Fifteen consecutive ridges were found to average 37' 8" from 

 rido-e to ridge, and 22" in amplitude. Above iSevern Bridge, on the contrary, 

 where the first of the flood comes almost as a bore and the ebb current, com- 

 mencing long after high water, runs strongly to the last, the sands when dry are 

 almost smooth. 



In estuaries where the sand-banks dry in tidal sand ridges, their size and direc- 

 tions afford at a glance a good idea of the course and velocities of the streams of 

 flood and ebb over these banks^ and of'en show by the steep face of the ripple in 

 what parts the flood or the ebb respectively is the stronger. The present position 

 of the lower portion of the rivers in the valleys of Aberdovey, Barmouth, and 

 Montrose is apparently due to the alongshore drift of beach material from the side 

 exposed to the greatest waves. To this are also due the D shape of their tidal 

 basins and the resulting circulation of the tide. The deep-water channel of the 

 ebb is down the straight limb of the D, which is close under the hills which bound 

 the valley, having been pushed as far as possible by the drift of beach material. 



Tidal" sHud ripples above low-water mark are not confined to estuaries, being 

 often found upon the st-a-shore in places where there are strong currents. They 

 face with the current, not with the swell, and are thus readily distinguished from 

 wave ripple-mark. Owing to variable direction of the currents in such situations, 

 the ripples are not generally in long straight ridges. It often happens that the 

 only traces of the tidal sand ripples left by the receding tide on the sea-shore are 

 pools, the characteristic section of which (like that of the print of a horse's iioof in 

 sand) indicates that analogy with the fuljes of the desert which is demonstrated 

 by the author's observations. 



The complete paper, illustrated by photographs, is intended for publication in 

 the 'Geographical Journal.' 



FRIDAY, SEPTEMBER 7. 

 The following Papers and Reports were read : — 

 1. Remarks on a Table of Strata. By Dr. H. Woodavard, F.K.S. 



Report on Seismological Observations. — See Reports, p. 59. 



3. Geological Notes on the Tlpway Disturbance. By Clement Reid, F.R.S, 

 Appendix to Seismological Report. — See Reports, p. 108. 



4. The Caves and Pot-holes of Inglehorough and the District. 

 By S. W. CuTTRiss. 



The portion of Yorkshire to which this paper refers is contained in Sheets 49, 

 50, and CO (New Series) of the 1-inch Ordnance Survey. The great Craven 

 Faults which traverse it in a N.W. to S E. direction have produced a difference of 

 level of the strata of several thousands of feet ; the limestones on the south side 

 of the Faults being far below the surface. 



The Silurian slates and grits form the basement beds, and are exposed in several 

 of the valleys. On these rests the Carboniferous Limestone, which has a thickness 

 of about 500 feet from the base to the present exposed surface on Inglehorough. 

 The name Carboniferous Limestone is here applied only to distinguish a particular 

 bed of rock in the district. Above this are a series of thinner limestones, shales, 

 and sandstones (the Yoredales of Professor Phillips) capped by Millstone Grit. 



