242 Ml. R. Biillen Newton on some 



They -weip forwarded l)y Dr. G. Arnold, Curator of tlie 

 Ehodesia ]\Iu.seuui, with tlie following remarks from Mr. H. B. 

 l^luufe, B.A., F.G.S., Director of the Geological Survey of 

 Rhodesia: — "The Clialcednny in which the Gastropods and 

 Plant-rcnmins discovered by Mr. A. J. C. Molyneux occur, 

 is found at the base of the Kalahari Sand, whicli is widely 

 spread in Northern Matabeleland. No other fossils are 

 known from these beds. They lie on a peneplain eroded in 

 Upjier Karroo Beds and are older than the present river- 

 system. The peneplain is younger than the Kiniberlite pipes, 

 sui)posed to be Upper Cretaceous, but any evidence of age 

 from palaiontological data would be most valuable." An 

 examination of these rocks proved them to be comjiletely 

 silicilied, having the ajtpearance 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 subjtcted to some 

 kind of erosion. From a study of the organisms, which 

 com]»rise small Gastropods resembling Viviparus and Palu- 

 det'triiia, and jdant-remains belonging to the genus Chara, 

 there is no doubt as to the freshwater origin of this deposit 

 and its rej)resenting a relic of an ancient fiuvio-lacustiine bed 

 or a former region of marsh-land. The moie prominent 

 fossils are restricted to the surface, although microscopical 

 sections of the flinty matrix ijidicatc 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 arc numbered 1350, 1351, and 1352, 

 may have their fossils thus briefly described : — 



Hock no. 1350. — This contains several fruits of Chara of 

 minute size bearing cxticmely fine spiral striations, which 

 are arranged longitudinally in tults 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 (PI. VIII. fig. 6). The surlace 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 apj)ear to be wider than those associated with 

 specimen no. 1352. There are scarcely any indications of 

 Gastropod remains in this rock. 



