It will have been observed in our consideration of the physiography of the north-eastern corner of the Northern Frontier Province of Kenya Colony that there is strong evidence in support of the existence of fault scarps, which date their first uprising from the Jurassic age. The evidence in the Coast Province in the neighbourhood of Mombasa is not so clear, but if we examine this in the light of that from the northern frontier, it will be seen that there is a strong suspicion that the coast ranges, too, are horsts, dating their first rise from the Jurassic.