528 
THE GEOLOGIST. 
rrossed on its middle tliird by numerous short parallel stripes of 'altcmatcly light 
and dark flint, and frequently terminated at each extremity by an irregular mass 
of flint, often clouded or grey. The axis occurs sometimes isolated, sometimes 
covered with a thin coating of grey flint only, and sometimes associated with only 
a few cross stripes of the banded structure. In some instances the banded flint 
has for its axis a sponge, or fragments of sponge. 
The author had not found in the banded flint any .sponge-tissue peculiar to it ; 
in some instances, however, a silicified sponge appears to have been traversed by 
alternate lines of the light and dark colour analogous to those of the banded flints. 
In some instances a concentric ai rangement of light and dark layers of flint occur 
around the two axes, or around isolated nuclei. Mr. Wetherell regarded this 
banded appearance in the flint as not being due to an organic structure, but to 
have originated in a peculiar arrangement of the siliceous matter around organic 
bodies, frequently long and stem-like, such as those of the Graphularia which 
supplied so many axial nuclei to the concretions in the London Clay. 
Nov. 17. — 5. "On some Fossils from South Africa." By G. W. Stow, Esq. 
At the close of 1850 Mr. Stow and his party fell back into the interior to avoid 
the KaiBrs ; in making this journey he collected largely the fossils in his route, 
and succeeded in preserving them on his return. In a plain at the foot of the 
Khenosterberg, which is a branch of Sneewbergen range, he met with patches of 
ground strewed with nodular concretions and fossil wood, probably derived from 
the neighbouring mountains. These mountains are composed of horizontal strata. 
Eight of the beds at the foot of the Rhenosterberg are sandstones ; above them are 
four layers of calcareous grit, or pebbly limestone, with other sandstones. These 
calcareous beds sometimes contain bones, but at one spot in the sandstone rock 
Mr. Stow discovered and chiselled out a nearly perfect skeleton of a small reptile. 
Other reptilian bones, and especially two small well-preserved skulls, rewarded his 
search ; one of these belonged to a small Dicynodon, the other to a little unde- 
scribed reptile. Mr. Stow sent numerous specimens of the numerous nodular 
concretions and septaria from the rocks of this place, and also specimens of the 
concretional and other trap-rocks of two dykes that crossed the plain. 
6. " On some Mineral Springs at Tehran, Persia." By the Hon. C. A. Murray. 
The chief point in this paper was the description of the Ab-i-garm, a spring of 
hot water rising at about 2,000 feet above the bed of the river Laur, on one of 
the spurs of the Demavend, a lofty and slumbering volcano. The principal mineral 
ingredients in tliis water are sulphur and naphtha, and its temperature at its 
source is about 150° F. 
7. "On Some Points in the Geology of South Africa." By Dr. R. N. Rubidge. 
The author had observed in Namaqualand the occurrence of horizontal siliceous 
beds covering other siliceous inclined beds, the silification of the latter being ap- 
parently due to the infiltratiou of silica from the upper quartzose beds into the 
inclined beds below. 
In this communication Dr. Rubidge details the evidences that he observed of 
such a process having taken place, and points out how the observations on some of 
the Namaqualand rocks by Mr. Bain, Mr. beil. and Dr. Atberstone, respectively, 
tend to support his views in this respect. The inclined beds of this district are 
gneissic, and, in the instance referred to, very quartzose. The horizontal sandstone 
of tliis district he correlates with the Table-mountain sandstones, but in them he 
has found only a few obscure traces of fucoidal or other plants. 
The author then passes on to the Cape district ; and, first offering his testimony 
to the industry and general exactitude of Mr. Bain as a geologist, lie proceeds to 
compare Mr. Bain's section of Mitchell's Pass with the section he made for him- 
self on two hasty journeys. 
Mr. Bain describes the indurated sandstone or quartzite in Mitchell's Pass as 
being, at first, horizontal, and then suddenly dipping at a short angle northward, 
so as to underlie the Devonian Schists of the Bokkcveld at ('ores, and to divide 
them from the slates of the Capo district. Dr. Rubidge points out the apparent 
difBculty of explaining such an inclination of the quartzite, the slates underlying 
