218 Geological Society : Dr. Stanger on the 



sandstone, not distinctly stratified, rendered vesicular by removal of 

 the iron on exposure to the weather. The iron occurs in concentric 

 laminae, and is found in masses occasionally powerfully magnetic. 

 Under the sandstone is seen, at several places, a stiff aluminous 

 clay containing fragments of wood. At a section at Kingstown 

 the sandstone is forty feet thick. Hyperstene rock forms the side of 

 the fort-hill and the tops of the hills around Sierra Leone. Neither 

 volcanic nor granitic rocks were observed in the neighbourhood. 



2. Liberia. — Monrovia. — The rocks in the neighbourhood of the 

 Mesurada river are greenstone. Ferruginous sandstone, similar to 

 that at Sierra Leone, occurs near the government house. The author 

 saw fragments of gneiss, but none in situ, and was shown a spe- 

 cimen of large granular granite, said to be found forty miles up the 

 country. 



3. River Sinoo, lat. 5 N., long. 9 W. — On the south side of the 

 river are small hills of gneiss, cut through in places by veins of 

 granite running in all directions, and in one place by a vein of trap 

 two feet wide, running W.N.W. and E.S.E. The author found 

 greenstone in the neighbourhood passing into hornblende rock, but 

 did not see its connection with the gneiss. The north bank of the 

 river is low land covered with sand, in which was found a fragment 

 of ferruginous sandstone like that at the preceding localities. 



4. Cape Coast Castle. — The castle stands on a mass of granite, 

 which is small-granular, and contains imbedded masses of horn- 

 blende slate. The felspar is flesh-coloured and in many places mixed 

 with the quartz, forming a beautiful variety of graphic granite. 

 About a mile north of the castle mica slate is seen in contact with 

 and dipping under the granite to the south at an angle of 40°. The 

 slate is not altered but much decomposed. Both granite and slate 

 are cut through by veins of quartz ; and in the town, a mass of mica 

 slate is seen imbedded in the granite, which sends veins into the 

 slate. In one place a greenstone vein, four yards wide, was seen 

 traversing the granite, itself again traversed by a vein of granite. 

 The mica slate is worn into valleys, and the granite stands up in 

 masses which have been erroneously regarded as erratic blocks. 



5. Accra. — The town is built on sandstone which dips to the 

 S.E., and has joints running W.S.W. and E.N.E. In mineral cha- 

 racter it resembles the new red sandstone of Liverpool. The surface 

 of the country about the Salt Lake, which is to the north of the 

 town and about thirty feet above the level of the sea, is a sandy 

 clay or loam containing great numbers of shells of the genera A chatina, 

 Area, Cytherea and Cerithium. At the farm on the hill, fourteen miles 

 from Danish Accra, the rock is quartz rock, white and red, dipping at 

 40° to the S.W. and traversed by joints at right angles to the dip. 

 The joints are redder than the general hue of the rock, which the 

 author regards as a metamorphic sandstone. 



The gold which is met with at Cape Coast Castle, Anamabre 

 and Accra, is procured from the sand by washing. This sand is 

 usually white, and contains iron and hornblende. The felspar at 

 Anamabre is green, and in some places between Accra and Cape 



