140 Reports and Proceedings — Geological Sociehj of London. 



The rocks described in this paper were o;iven to the author by 

 Mr. C. W. Hobley. Mount Zombo, situated in long. 39° 13' E. and 

 ]at. 4° 26' S , and 1,519 feet high, is a massif of coarse-grained 

 eleeolite-syenite, consisting of anorthoclase, el^olite, usually allotrio- 

 morphic, and tegyrine. The rock must occur in the belt of Duruma 

 Sandstone, unless the fossiliferous Jurassic shales run westward up 

 the low valley of the Umba Eiver. Associated with this massif 

 is a series of dykes belonging to the olivine-less variety of 

 monchiquites known as fourchites. Their phenocrysts consist of 

 plagioclase, probably oligoclase, hornblende, and fegyrine, but 

 augite and ilmenite are also present ; the groundmass contains 

 a certain amount of analcite. 



Unfortunately there is some doubt as to the exact age of the 

 Duruma Sandstone into which the fourchites are intrusive. The 

 author gives an account of the different opinions as to the age of 

 these rocks ; the evidence at present available is only sufficient to 

 prove that they are post-Carboniferous and pre-Callovian. The 

 sedimentary series on the coast-lands of British East Africa and 

 IJsambara, in his opinion, may be previously arranged as follows : — 



5. Pleistocene reefs, limestones, alluvium, and laterites. 



4. Jurassic shales and sandstones ; Kimeridgian, Oxfordian, and Callovian. 



3. Possibly a pre-Jurassic part of the Duruma Sandstone. 



2. Magarini sandstones ; ? Triassic. 



1. Sabaki shales ; Upper Carboniferous. 



It is therefore probable that the igneous rocks are not older than 

 the early Mesozoic, and may be Jurassic or post-Jurassic. 



III.— February 7, 1900.— W. Whitaker, B.A., F.E.S., President, 

 in the Chair. The following communications were read : — 



1. " Foraminifera from an Upper Cambrian Horizon in the 

 Malverns." By Frederick Chapman, A.L.S., F.R.M.S. (Com- 

 municated by Prof. T. T. Groom, M.A., D.Sc, F.G.S.) 



The foraminifera described in this paper were found in a shaly 

 limestone which Professor Groom obtained " from the debris of 

 a small ridge composed of black shales, with intercalated basalts, 

 which forms a spur on the north-west side of Chase End Hill. 

 The rock belongs to the well-known and widely-spread zone of 

 ' Splicer oplitlialmus, Peltura, and Ctenopyge, which in Britain forms 

 the upper half of the Dolgelly Beds or tipper Lingtda-Flags." Tlie 

 specimens have been sliced, and have yielded a few forms other 

 than SpirilUna ; sections of echiuoderm-spines, ostracod-tests, and 

 •occasionally sponge-spicules (?) are also to be seen in the slides. 

 The tests of the foraminifera are infilled with a crystalline substance. 



The following species are mentioned : Lagena Icevis, Montagu, 

 L. apiculata, Eeuss, Z. ovum, Ehrenberg, Nodosaria pygmcea ('?), 

 Terquem, N. abnormis (?), Eeuss, Margimda sohita (?), Eeuss, 

 Cristellaria aculauricidaris (?) (Fichtel & Moll) ; and a new species 

 of SpirilUna is described. The Spirillince are in a good state of 

 preservation ; and the valves of moUusca, cut through in section, are 

 sometimes seen to be quite filled with the tests of this genus. 



