84 Repo74s and Proceedings. 



G. Gilfillan, Esq. Communicated by W. W. Smytli, Esq., F.E.S., 



F.G.S. 



Mr. Gilfillan described Ms going through Colesberg to Hopetown, 

 and thence across the Orange Eiver to Backhouse ; and then, after 

 crossing the Vaal, up its right bank as far as Lekatlong. He noticed 

 such diamonds as he saw or heard of, and described the locality as 

 being thickly coated with sand, diamond-bearing gravel, and tufa, 

 hard blue shales occurring here and there in protruding hills. 



Discussion. — Prof. Tennant stated that he had lately seen as many as 500 diamonds 

 from the South- African fields in the possession of one person, some weighing as much 

 as 50 carats. He had seen another fragment of a stone which must have originally 

 been at least as large as the Koh-i noor. 



II. December 21, 1870.— Joseph Prestwich, Esq., F.E.S., Presi- 

 dent, in the Chair. The following communications were read : — 



1. " On Lower Tertiary Deposits recently exposed at Portsmouth." 

 By C. J. A. Meyer, Esq., F.G.S. 



The author described some exposures of Lower Tertiary deposits 

 made during excavations for the " Dockyard Extension Works " in 

 Portsmouth Harbour. The thickness exposed, exclusive of alluvial 

 deposits, amounted in all to 127 feet. The beds dip S.S.W., or 

 nearly south, 2^ to 3 degrees. The author grouped them under the 

 four following divisions, in ascending order : — 



1. Clays and sands with pyrites 36 feet 



2. Argillaceous sands with i)e«<a^w?» 25 „ 



3. Sands with i«w^M^a 8 „ 



4. Clays with Ci/^rwa and sandy clays 55 ,, 



The author indicated the fossils contained in each of these divi- 

 sions, remarking upon the range of some of the species, and upon the 

 apparent mixture of London clay forms with others usually regarded 

 as characteristic of higher or lower beds, which occurs especially in 

 the " X^7^^^tZa-sands." He suggested that, as the species found here 

 •present some slight differences from those occurring in other de- 

 posits, the difficulty might be got over on Darwinian principles. 

 The author considered that the fossils did not furnish any satisfactory 

 evidence of the true position of these beds ; but, from stratigraphical 

 evidence, he regarded them as being included in group 3 aud part 

 of group 4 of Mr. Prestwich's section of the Whiteclifif strata in 

 the Isle of Wight. He concluded with some remarks on the super- 

 ficial deposits consisting of gravel and old and recent mud overlying 

 the Tertiary beds in the section described by him. 



Discussion. — Prof. Eamsay called attention to the value attaching to such obser- 

 vations as those of the author on the nature of the superficial deposits as distinct from 

 the older rocks on which they repose. 



Mr. Etheridge observed that the presence of the Lingula determined the position 

 of the Bognor beds in the series, though there appeared great difiiculty in fixing it 

 stratigraphically. The commingling of species exhibited in this instance of shells 

 hitherto supposed to be peculiar to certain horizons, he regarded as very remarkable. 



Prof. Morris observed that the section seemed to show, not only the order of the 

 beds, but their manner of deposition, the whole having formed part of a tranquil sea- 

 bottom. He remarked on the difficulty of separating the more recent mud deposits 

 from the beds of more ancient date. He pointed out the method of formation of 

 septaria apparently by segregation, as they sometimes included undisturbed parts of 



