H. B. Maufe — Coastal Series of Sediments, E. Africa. 275 



remarks that I believe them to be of Karroo age, and then says, 

 " E. Fraas, who subsequently made a brief examination of the line of 

 railway, and whose account of the geology of the l'egion differs in 

 manv respects from that of Maufe, refers them to the Middle Dogger 

 (Inferior Oolite)." 1 



I cannot explain how Fraas' paper came to be overlooked by me, 

 or that author's reading of the structure and succession would certainly 

 have been challenged at once. Fraas' examination was made whilst 

 detained in Mombasa for a day or two waiting for a steamer. He 

 apparently travelled up and down the Uganda Railway by train, and 

 was able to make excursions from a couple of the stations. I had the 

 advantage of several weeks on the ground, both trolley ed and walked 

 the whole line, and made several traverses out on both sides where 

 sections might be seen on the flanks of valleys. 



Between Yoi (mile 102) and Kilindini on the coast Fraas makes 

 seven rock groups, which in ascending succession are as follows : 

 (1) Crystalline basal rocks, (2) Karroo sandstone, (3) Middle Dogger, 

 (4) Upper Dogger, (5) Malm, (6) Cretaceous sandstone, (7) Pleistocene 

 reef limestone. 



According to Fraas' description and section the crystalline basal 

 rocks crop out at Yoi, and the dip being eastwards towards the coasts 

 the other groups outcrop in order in that direction with the exception 

 of (6) Cretaceous sandstone, which, owing to a supposed flattening of 

 the dip, does not reach the coast. The Pleistocene reef (7) rests 

 unconformably against his (5) Malm. 



Between Yoi and Maungu, the next station towards the coast at 

 mile 84, Fraas states that (2) Karroo sandstone crops out, and also 

 says, " South of the railway the Maungu Mountains rapidly rise to 

 a height of 1,000 metres. We easily recognize these as sandstone 

 mountains with horizontal stratification, and a light-coloured, cross- 

 grained sandstone is to be seen along the railway." I climbed these 

 'mountains' and found them to consist of a foliated hornblende- 

 biotite-gneiss (Report, p. 19). Also, I am sure the whole distance 

 from Yoi to beyond Maungu is underlain by gneiss, and any sandstone 

 seen beside the railway must have been brought there for construction. 



At Mombasa Fraas saw a big trunk of silicified wood which he 

 was told came from this region. The trunk is without doubt one 

 which I dug out of his (6) Cretaceous sandstone and took down to 

 Mombasa station. (Report, p. 9.) 



Around Samburu (mile 41) he notes the hard micaceous sandstones 

 which he says are (3) Middle Dogger. These are my Taru Grits, 

 which were being quarried for the Kilindini harbour works. He 

 examined them more closely there, and found poor impressions of 

 Calamite-like stems, and fragmentary leaf-remains, also one cross- 

 section of a Belemnite and one skeleton impression of an Ammonite. 

 I saw only obscure plant-remains and black carbonaceous specks in the 

 beds at Samburu. Beyond Samburu Fraas identifies from the train 

 the sandstones of the Upper Dogger (4). These are probably the 

 lower part of the Maji-ya-Chumvi Beds, in which I found Thuyites 

 and Carpolites. 



1 Centralblatt fur Mineralogie, etc., 1908, p. 641. 



