In the Willamette Valley the soils are mostly clay loams, of a basaltic nature on the foothills and greatly enriched in the river bottom lands by washings from the hills and by deposits of rich black humus.
The spurs consist in some cases of white chalk covering the limestone, and on the south there are several basaltic outbreaks.
Deep, with steep walls of basaltic and kindred rocks.
Above Deir, where lie the ruins of Halebiya, the river breaks through a basaltic dike, el-I;Iamme, some 300 to 500 ft.
East of the Buttauf extends the basaltic plateau called Sahel el Ahma ("the inaccessible plain"), rising 1700 ft.