232 Geological Society : — 



With these two series of results as ordinates, curves were drawn 

 representing times and ranges of actual diurnal tide, which were thus 

 presented in a convenient form for comparison with the diurnal tide 

 which had been previously calculated. 



The comparison confirmed the previous conclusion that the tide 

 based on the simple declination theory was insufficient ; and the em- 

 pirical correction which had been adopted seemed to provide an ap- 

 proximation to the required addition to it, both in time and height. 

 But it appeared that a better coincidence in time would have been 

 obtained by assuming the diurnal tide at Kurrachee to be forty 

 minutes earlier. This supposition was tested by treating the obser- 

 vations of 186.5 in a similar manner, and also by recalculating a 

 portion of the tides of 186/ with the earlier diurnal tide. In both 

 cases the supposition was confirmed, a better agreement being ob- 

 tained. 



On treating the Bombay observations in the same manner, a fair 

 general coincidence with the calculated diurnal tides was found to 

 exist ; but it was further found, on comparing together the Kur- 

 rachee and Bombay curves of actual diurnal tide (thus for the first 

 time recorded for the same period), that the times were nearly iden- 

 tical at the two ports, and the range at Bombay about one-tenth 

 greater than that at Kurrachee. 



The tables for the four months over which the Bombay observa- 

 tions extend were recalculated with the diurnal tides which had been 

 calculated for Kurrachee (but made forty minutes earlier, and in- 

 creased in range by one-tenth) ; and the result was quite as good as 

 that shown by the original tables. This fact would seem to point 

 to fthe possibility that the diurnal tide is a vertical undulation, 

 acting simultaneously, or nearly so, over a large area. 



GEOLOGICAL SOCIETY. 

 [Continued from p. 158.] 

 May 6th, 1868.— Prof. A. C. Ramsay, LL.D., F.R.S., Vice- 

 President, in the Chair. 



The following communication was read : — 



" On the Quaternary Gravels of England." By Alfred Tylor, 

 Esq., F.L.S., F.G.S. 



Mr. Tylor first compared, by means of sections and models, the 

 gravels of the Aire Valley at Bingley, of the Taff Vale between 

 Quakers' Yard Junction and Aberdeen Junction, and of the Valley 

 of the Rhonda near its junction with the TafF. He then described 

 the cave-section of Bacon Hole, Gower, and the sections exposed at 

 Crayford, Erith, and Salisbury, comparing the angles of deposition 

 of gravel-beds concealing the escarpment of the chalk in these last 

 three localities with the same conditions at Brighton and Sangatte. 



By comparing the gravel-beds at different levels, and upon strata 

 of different age and configuration, he showed in what respect they 

 differ from each other. The bulk and height of the Quaternary de- 

 posits had strengthened the conviction which he expressed in his 

 previous paper (on the Amiens gravel), that there was a long period, 



