Yorubaland may be divided into three great zones, one of very little use to the farmer as farmland, but of service to him as the zone that in the olden days provided him with salt, i.e. the Mangrove belt. Here the seaside inhabitant used to cut down the salt bush and manufacture salt, which he sent with smoked fish into the interior, and exchanged for farm produce. Here also oyster shells were burnt and lime made, but this does not appear to have been used by the farmers, and I think we may conclude that the industry was acquired from the early white settlers. The native farmers have long known that leguminous crops nourish the land, but they have not yet learnt the use of lime as a manure, although it is perhaps the manure most needed in this country.