Dr. F. H. Hatch—A Peridotite from Kilimanjaro. 257 
are filled up with white crystalline infiltrations. One of these 
fissures, passing right through the central portion, gives off there a 
small quantity of a brown fluffy material, perhaps ferruginous. 
No organic tissue seems to be traceable ; and with this view it is 
interesting to find an inorganic so closely resembling an organic 
structure. It might well pass for Cryptozoon were the figure only of 
that form known to us, without its detailed description. 
The specimen has now been deposited in the British Museum 
(Natural History), where a section has been cut from the face of the 
mass, so as to permit of a more exact examination of its structure. 
The following is an extract from a letter to the Editor received 
from Prof. H. A. Nicholson, D.Sc., F.G.S., and gives the expression 
of his opinion after an examination of the Kulu limestone :— 
«T have made a careful examination of the slide of the ‘Kulu’ 
specimen which you sent me, so far as its condition allows. I am not 
prepared to give any positive opinion about it, but have no hesitation 
in saying that, so far as I can judge, it is certainly organic; but that 
the organism (whatever may have been its nature) has been subjected, 
subsequently to entombment, to great alteration by pressure and 
crystallization. I have seen and examined very similar specimens, 
from both Silurian and Devonian strata, where one had unquestion- 
ably to deal with an organism, but where precisely similar alterations 
had taken place. Thus, masses of Heliolites Graye and Heliolites 
porosa often occur in this condition. Stromatoporoids also very often. 
Some of the things which M. Dupont has described from the altered 
Devonian Limestones of Belgium under the name of Stromatactis are 
of avery similar character. I have examined specimens of these, 
and while some appear to be due to a peculiar crystalline structure 
produced by inorganic causes, others seem to be certainly organic, 
and to be due to the action of pressure and crystallization, upon such 
organisms as Heliolites porosa and some of the Stromatoporoids. So 
far as your ‘ Kulu’ specimen goes, I should not like to be dogmatic 
either way, but it is (to say the very least) quite as likely to be an 
altered fossil as a mere concretion. It shows, in fact, some features 
which would strongly incline me to the view that it is the former.— 
Aberdeen University, Feb. 20th, 1888.” 
TV.—On a Horneienps-HyperstHene-PeripotTite From Lositwa, 
A LOW HILL IN Tavera District, at THE S. Foor or Kriima- 
ngaro, EH. AFRICA. 
By Freperick H. Harcn, Ph.D., F.G.S., H.M. Geological Survey. 
SMALL series of rock-specimens, consisting chiefly of fragments 
of basalt, dolerite, volcanic conglomerate and tuff, which were 
collected near Kilima-njaro, by F. Holmwood, Esq., C.B., late 
Consul-General at Zanzibar, was recently forwarded to the Museum 
at Jermyn Street, and placed by Dr. A. Geikie in my hands for deter- 
mination. Among these specimens was a small block, the crystalline 
texture and high density of which at once arrested attention 
DECADE III.—VOL. V.—NO. VI. 17 
