242 Mr. R. Bullen Newton on some 
They were forwarded by Dr. G. Arnold, Curator of the 
Rhodesia Museum, with the following remarks from Mr. H. B. 
Maufe, B.A., F. G. S., Director of the Geological Survey of 
Rhodesia :—* The Chalcedony i in which the Gastropods and 
Plant-remains discovered by Mr. A. J. C. Molyneux occur, 
is found at the base of the Kalahari Sand, which is widely 
spread in Northern Matabeleland. No other fossils are 
known from these beds. They lie on a peneplain eroded in 
Upper Karroo Beds and are older than the present river- 
system. ‘The peneplain is younger than the Kimberlite pipes, 
supposed to be Upper Cretaceous, but any evidence of age 
from paleontological data would be most valuable.” An 
examination of these rocks proved them to be completely 
silicified, having the appearance of a flint within and 
possessing a similar conchoidal fracture. Externally two of 
the specimens are of a rough sandstone character of reddish 
brown or straw-colour, due possibly to weathering by 
exposure, while the third example is of similar reddish colour 
but much smoother, having been probably subjected to some 
kind of erosion. From a study of the organisms, which 
comprise small Gastropods resembling Viviparus and Falu- 
destrina, and plant-remains belonging to the genus Chara, 
there is no doubt as to the freshwater origin of this deposit 
and its representing a relic of an ancient fluvio-lacustrine bed 
or a former region of marsh-land. The more prominent 
fossils are restricted to the surface, although microscopical 
sections of the flinty matrix indicate their existence throughout 
the rock, but in a distinctly more comminuted state. It 
should be noted also that the Chara remains are quite abun- 
dant, whereas the shells are of rarer occurrence. 
DESCRIPTION OF THE FOSSILS. 
The rocks, which are numbered 1350, 1351, and 1352, 
may have their fossils thus briefly described :— 
Rock no. 1350.—This contains several fruits of Chara of 
minute size bearing extremely fine spiral striations, which 
are arranged longitudinally in tufts of two or more at slightly 
distant intervals, being sometimes represented by cavities in 
which the fruits have disappeared, although leaving behind 
as mural impressions the familiar markings of their external 
conformation (Pl. VIII. fig. 6). The surtace of this rock is 
rather eroded, being smoother than the others, which renders 
the stem-structures of the Chara too obscure for definition, 
although they appear to be wider than those associated with 
specimen no. 1352. ‘There are scarcely any indications of 
Gastropod remains in this rock. 
