400 Dr. H. Woodward—Supposed Pholas-borings, Fayiim. 
of Gar el Gehannem. The height was determined as 156 metres 
above the Birket el Qurin, or 112 metres above sea-level, and we have 
every reason to believe these figures to be approximately correct. 
Up to the present time borings at this altitude have not been met with 
in any other locality.” 
In Mr. J. E. 8. Moore’s book Zo the Mountains of the Moon, 
Tanganyika Expedition, 1899-1900 (published 1901), p. 160, the 
author writes—‘‘The water's edge [of Lake Kivu] is generally 
fringed with bushes and ¢all reeds, which grow thickly together, and 
the land rises so steeply into the grass slopes behind that it is 
exceedingly difficult to get on shore at all from a boat. In conse- 
quence of this peculiar character of the shores there are hardly any 
places where there are sand-beaches or rocks, and it was only after 
I had been paddling about for an hour, and scanning the innumerable 
islands with my glasses, that I saw a low rocky shore on the left, on 
which I landed. It was a most extraordinary place, backed up by 
a steep green hill. The rocks which I had seen consisted of strange 
rounded masses like the surface of a pudding, and, wherever they were 
wet by the ripples of the lake, were covered with green Cladophora and 
slime, and in places they rose up into weird stony trunks, like those 
on the old coral beaches one sees about Mozambique. These upstanding 
lumps were, moreover, pierced with holes, as if they had been prepared 
for blasting operations, and for the life of me I could not find out for 
a long time what they were or how they had been formed. When 
I broke off a portion, moreover, I found to my intense surprise that 
the stone was full of fossil shells; there was an unmistakable planorbis 
and some conical forms, probably melanias. But what animal had 
bored the long straight holes, about an inch in diameter, which ran 
parallely through the mass? I could not make this out, but after 
a time I found one mass with an old partially fossilized reed-stem 
filling up one of the holes, and then the mystery was suddenly solved. 
The holes were the casts, in a lake deposit of some kind, of reeds that 
had once grown there. That this was so soon became certain, for 
I found several clumps of old dead reed-stems already becoming 
covered up with a curious incrustation from the waters of the lake 
which forms about them, and other similar structures. In other 
places this substance, which turns out to have a high percentage of 
carbonate of magnesium, binds the loose pebbles of the shore into 
masses of conglomerate, which are as hard as if they had been made 
of Roman cement’’ (p. 160). 
Having been so fortunate as to haye seen and examined the 
specimen sent home by Mr. Beadnell and figured above, and also 
the hand-specimen from Lake Tanganyika obtained by Mr. Moore, 
I may venture to pronounce upon the identity in their character, and 
to express the opinion that the perforated blocks from the Faytm are 
not the work of boring mollusca in rock, but that the sandy calcareous 
material, which is similar to that from Lake Tanganyika, has been 
accumulated around the stems of reed-like water-plants as a more or less 
concretionary deposit precipitated from the waters of the present lake 
or from those of its more extensive predecessor, Lake Moeris, around 
the shores of which grew in abundance large clumps of these tall reeds 
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