398 Dr. H. Woodward—Supposed Pholas-borings, Fayim. 
certainly produced by the action of eddies. They would probably 
produce interesting results when studied by a well-trained physicist 
on the spot. The last stage in the formation of dreikante is reached 
when the pebble is reduced to an almost flattened little plate, which 
is sooner or later reduced in size to a mere sand-grain. Again, one 
can observe this reduction in all stages on the desert. Actual experi- 
ment with laboratory conditions proved that these three-edged stones 
could not remain with their pointed ends facing a strong air current, 
but that they invariably tended to set themselves broadside on towards 
it. This is consistent with the explanations given above, and to some 
extent confirms them. 
The following short bibliography will perhaps be useful to those 
who are interested in these-and other kindred phenomena :— 
1. J. Warrner. ‘ Uber Ergebnisse, einer Forschungsreise auf der Sinaihalbinsel 
und in der Arabischen Wiiste’’: Verhandl. den Ges. f. Erdkunde z. Berlin, 
1888, Bd. xv, No. 6. 
—— ‘‘Die Denudation der Wiiste’’: Abhandl. math.-phys. Classe d. Konigl. 
Sachs. Ges. der Wissensch., Leipzig, 1891, vol. xvi, pp. 847-569. 
bo 
3. —— ‘ Das Gesetz in Wustenbildung in Gegenwart und Vorzeit’’ ; Berlin, 1900. 
4. J. H. WoopwortH. Amer. Journ. Sci., 1894, xlvii. 
5. Verworn. ‘‘ Sandschliffe von Djebel Naktis, ein Beitrag zur Entwickelungs- 
geschichte der Kantengerolle ” : Neues Jahrb., 1896, i, p. 200. 
6. E. Harz. Compt. Rend. Géol. Soc. France, 1900, p. 30. 
7. O. Aner, Jahrb. k. k. Geol. Reichs., 1902, p. 24. 
8. Srrenstrup. Geol. Foren. Stockholm, x, p. 485; xiv, p. 498. 
9. M. Cuotsy. Docwments relatifs a la Mission dirigée au Sud de 1’ Algérie, 
1890, p. 327. 
10. T. Barron & W. F. Hume. Topography and Geology of the Eastern Desert 
of Egypt ; Cairo, 1902. 
See also F. A. Bather, ‘‘ A wind-worn Pebble in Boulder-clay,’’ Guon. Mae., 
1905, p. 858; and ‘Wind-worn Pebbles in the British Isles, etc.’’, Proc. Geol. 
‘Assoc., vol. xvi, pp. 896-420, pl. xi, 1900 (with references to eighty -seven papers on 
dreikante and other wind- -polished stones). 
V.—Own soME SUPPOSED PHOLAS-BORINGS FROM THE SHORES OF BIRKET 
EL Qurotn, THE ANCIENT Lake Moents, or THE Faytm, Eeyrr. 
By Henry Woopwarp, LL.D., F.R.S. 
N a review of Mr. H. J. L. Beadnell’s important Memoir on the 
Topography and Geology of the Faytm Province of Egypt, 
published by the Egyptian Geological Survey in 1905,! I briefly 
referred in passing to some “curious blocks of sandstone, pierced by 
numerous borings’’, described by the author, and I added, ‘“they 
appear to be the exact replica of specimens brought home from Lake 
Tanganyika by Mr. J. E. 8. Moore” (p. 519). 
Mr. Beadnell writes in his memoir at p. 71—‘‘ Borings on Rock- 
surfaces; of doubtful age. There are within the Faytim depression 
numerous rock-surfaces pierced by borings, apparently the work of 
marine boring mollusca but naturally offering no exact evidence as 
to their age and origin. These borings are found at two distinct 
levels, approximately from zero to 20 metres above sea-level and at 
112 metres above sea-level. 
1 See Guo. Mac., 1905, pp. 516-19. 
