In desert or semi-desert regions such as North Africa, all equipment is truck-mounted and movement over desert and sand-dunes is comparatively easy. Field-work continues throughout the year in good working conditions except for the summer months when temperatures rise above 100°F, and during heavy sand-storms. The tented base camp does not move very often as a wide area can be covered conveniently from each camp site. The party is supplied by truck from the nearest town and only personnel and urgent supplies travel by air.