Seeking Spanish mud/clay

Hello all; We're traveling through the Costa del Sol area of Spain for a few weeks, and I'm on the lookout for good mud, clay pits, etc. Our travels will take us along the coast from Cadiz in the East (By Gibraltar) through to Cartagena. Anyone ever been? I thought I'd have more luck on the Splosh forums than umd, because there's more of a Euro crowd here, but I've posted both top make sure no-one is missed.
Thanks to anyone with advice.
Thanks to anyone with advice.
