290 Captain P. 8. Lelean, B.A.M.C.— 



Taunnsian beds of Looe and Fowey. These rocks I propose to 

 correlate with the Gedinnian of the Continent in a subsequent paper. 

 I may mention that at Looe I have at last found the most 

 characteristic fossil of the Taunusian series, Onychia (Kochia) 

 capuliformis, Sandberger, as well as Spirifer merciirii (Gosselet). 



II. — An Eocene Outcrop in Central Africa. 



By Captain P. S. Lelean, E.A.M.C, F.R.C.S.Eng. 



(With a Map in the text. ) 



AT the heart of Africa lies a vast area, so remote, so inaccessible, 

 and hence so little known, that for the explorer it possesses 

 a fascination all its own. The interests of the geologist have perhaps 

 received less recognition than those of his fellow-scientists from the 

 pen of the traveller ; and there must be much that he would wish 

 to know lying hidden in these distant regions awaiting discovery 

 and publication. There is thus an encouragement to make known 

 any facts which may throw light upon the geological structure of 

 those parts, however small the contribution may be. 



While serving recently with the Anglo-French Boundaiy Com- 

 mission (Niger-Chad) we found an outcrop of a fossil-bearing 

 stratum in the region of the Sokoto, having, as shown in the 

 accompanying map, giving its latitude and longitude, a position near 

 the verge of the Great Sahara Desert. On my return, the specimens 

 secured were submitted to the palteontologists of the British 

 Museum, one of whom, Dr. F. A. Bather, has kindly drawn up the 

 description which follows in a separate paper. For me it only 

 remains to give a few particulars of the general and localized 

 formation to supplement his account. 



Generally, the country consists of sandy plains, roughly estimated 

 as lying some 500 or 600 feet above sea-level. These plains are 

 traversed by watercourses, which contain running water only for 

 some five or six weeks in the year, the rainfall of 535 mm. lasting 

 during three months. A permanent water-supply is obtained by 

 deep wells, which in some places reach a depth of 400 feet before 

 tapping a constant source. 



From the plains rise hills in isolated masses or in chains, with 

 abrupt slopes, often almost precipitous, and with summits ending 

 at from 300 to 400 feet in plateaux of remarkably uniform height, 

 unbroken by further elevations. These hills consist mainly of 

 laterite, marl, and limestone, but in places are found outcrops of 

 syenitic granite; among minerals are some calcite, a little quartz, 

 and considerable quantities of mica. 



The accompanying map, kindly furnished by Capt. C. St. Foulkes, 

 E.E., shows to the east of Garadimi a plateau with the characters 

 described. Its steep sides are covered by boulders and detached 

 rocks of all sizes, and the formation is of laterite throughout. From 

 this plateau a long promontory reaches out towards Garadimi, falling 

 abruptly for some distance to merge into a spur composed entirely 



