Columbia subject headings:
Duricrusts--Mauritania.
Duricrusts--Senegal.
Laterite--Mauritania.
Laterite--Senegal.
Petrology--Mauritania.
Petrology--Senegal.
Rocks, Calcareous.
Harvard subject headings:
Princeton subject headings:
Duricrusts--Mauritania.
Duricrusts--Senegal.
Laterite--Mauritania.
Laterite--Senegal.
Petrology--Mauritania.
Petrology--Senegal.
Rocks, Calcareous.