418 Miss C. A. Raisin—Rocks from Somali Land. 
many obscure Foraminifera, such as Amphistegina (?); and there 
are also remains of Polyzoa (?). 
(3.) Limestone from Hilo. The slides of this rock exhibit :— 
Fragments of Lamellibranch shells, of Polyzoa, of (?) a plate of an 
Kchinoderm, and Gorgonia-like spicules. 
Foraminifera :—Lagena, Globigerina, Textularia (common), Pla- 
norbulina, Rotalia, Miliola, sections of specimens having affinities (?) 
with Miliolina, and rather Trochammina-like in form. 
The general facies of this fauna is characteristic of late Cretaceous 
and of Tertiary formations, but if the forms doubtfully identified as 
Amphistegina belong to that genus, its occurrence, fairly abundant, 
would rather suggest that the limestone may be of Miocene age, and 
thus possibly contemporaneous with that of Socotra.? 
From certain miscellaneous specimens, we may infer that flint and 
chert, containing traces of organic remains, were formed in connection 
with the calcareous rocks. The deposition of a ferruginous material 
is everywhere emphasized in sands and grits, in the coating of larger 
pebbles, and in irony concretions, recalling the description of a 
neighbouring locality where the ground was said to look as if strewn 
with iron slag.’ 
The district, illustrated by these rock fragments, is evidently one 
in which the foundations of the hills are composed of gneisses and 
schists, which are laid bare in the valleys, possibly in association 
with granite. Among these rocks, there are evidences of the action 
of pressure, and thus, in the higher ranges further inland, this 
gneissic series may be raised to a greater elevation and may form 
a larger part of the mass, as in the place where Sir F. Burton describes 
walls of rock full of glittering mica.* The central massif would be 
concealed beneath gently stratified sedimentary beds. Some of these 
are grits and sandstones, which mark the results of a denudation of 
older crystalline rocks, others are limestones, sometimes Foraminiferal. 
The crystalline series is found to the eastward, as shown in the 
sections from Somali Land published by Dr. A. T. de Rochebrune * 
from notes brought back by M. Révoil, and still further eastward in 
the Island of Socotra.’ Northward, similar rocks occur in Abyssinia ° 
and Egypt, and in the peninsula of Sinai. Sandstones and limestones 
have a similarly wide extension, although further evidence is needed 
to fix the exact age and correlation of these formations in the Hilo 
district. Some of the sandstones seem, lithologically, rather like those, 
which Dr. Rochebrune compares with the older sands of Nubia and 
of Adigrat; the overlying calcareo-argillaceous rocks he identifies 
by their fossils as of Neocomian age. Thus the rocks, described in 
this note, vary in some details from those of neighbouring localities, 
yet bear out, on the whole, the inference of Professor Bonney as to 
the wide extension which has characterized former geological con- 
ditions in North-eastern Africa. 
1 Phil. Trans. 1883. 2 «First Footsteps in Africa,” p. 391. 
3 « First Footsteps in Africa,” p. 396. 
* Faune et Flore des Pays Comalis, G. Révoil, 1882 (Observ. Géol. Dr, A. T. 
de Rochebrune). 5 Phil. Trans. 1888. 
° Geology and Zoology of Abyssinia, W. T. Blanford. 
