II 



colony and Ashanti, and occur on the western side of the Northern 

 Territories. From the coast they extend generally in a north-easterly 

 direction inland from east of Accra to the mouth of the Ankobra River, 

 west of Axim. They form the Akwapim, Atiawa, and Moinsi ranges 

 and the hills of the western frontier, besides numerous ridges and 

 hills in the intermediate geographical zone. These rocks strike 

 generally north-east to south-west. They are widely folded in parts, 

 but intensely folded, and to a less extent much contorted along 

 numerous and well-defined zones parallel with their strike. 



" In the eastern portion of the colony on the Krobo and Shai 

 Plains, extending back from the coast from near Accra to beyond 

 Prampram, is a great mass of gneisses, amphibolites, sheared pegmatites, 

 etc., having the same genera] strike as that of the altered sediments. 

 Their exact relation to these sediments has not yet been proved, but 

 undoubtedly large parts of them are completely altered sediments which 

 have undergone greater metamorphism than those specified. All of 

 these rocks probably belong to periods ranging from early Palaeozoic 

 to Pre-Cambrian. Through these altered rocks are numerous in- 

 trusions of granite and diorite, porphyry, pegmatite, and other allied 

 rocks throughout the country. In some places these intrusive rocks 

 have shared in the great dynamic changes undergone by those they 

 have intruded ; in others they are of normal character. 



" These altered sediments and igneous rocks are overlain over 

 large areas by widespread and much younger sediments — flat-bedded, 

 slightly inclined conglomerates, grits, sandstones, shales, mudstones 

 and limestones, principally of shades of chocolate and red, but also 

 of greyish-green and yellow. They occupy almost the whole of north- 

 eastern and northern Ashanti, and the southern, eastern and middle 

 portions of the Northern Territories. In addition, they occur along 

 the coast from Elmina to near the mouth of the Prah River, and from 

 the east of Sekondi to near the Butre River. All these rocks, except 

 those on the coast-line, have so far proved barren of fossils, while the 

 coastal group has yielded only a few of indeterminate character. The 

 age, therefore, of these rocks is unknown. 



" A series of clay-shales, mudstones and sandstones at Accra 

 appears to belong to the same division. In the Beyin district, on the 

 western portion of the coast-line, there are small outcrops of a yellow 

 limestone with fragmentary fossils ; it probably belongs to the Eocene 

 period. Some of the marine terrace gravels and pebbles and bouldery 

 clay along the coast-Une may be of Pleistocene age, while the Recent 

 deposits comprise river gravels and sands, alluvium, swamp and 

 lagoon muds and beach sands and dunes forming at the present time. 

 " It should be borne in mind that very large portions of the country 

 are still quite unknown to the geologist. 

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