All information on soils were from the Land Resource Study 20 series of books
(Volumes 1 to 5), published by the Land Resources Division, Ministry of Overseas
Development , UK.
Tapang Association occurs on low hills and terraces in the Labuk and Karamuak
valleys. A notable occurrence is on the broad lowland linking the Labuk valley
at Telupid with the Karamuak valley at Enteleben.
The low hills are up to 30 m
in amplitude with slopes of less than 15°.They are surrounded by slightly
undulating terraces. The hills are formed of basic igneous rocks and the
terraces are formed of alluvium derived from adjacent mountains of basic and