This is an agglomerate pipe 50 m in diameter that was intersected by an inclined borehole.
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The Moroto volcano covers an area of approximately 25x15 km and rises to just over 3000 m, about 1500 m above the surrounding plains.
A cylindrical plug of olivine melanephelinite of about 400x200 m forms the hill of Murulinga. Abundant phenocrysts of diopside and fewer of olivine (Fo82) are set in a groundmass of clinopyroxene, nepheline, olivine, magnetite, a pale mica, sodalite and pyrite.
A dyke of olivine melanephelinite, similar to the rock of Morulinga (No. 17), 50 m wide and 380 m long occurs on the hill of Matany 11 km west of Morulinga.
The hill of Kurithai is built of a circular, 400 m-diameter plug of nephelinite which consists of pale green clinopyroxene, subhedral nepheline and magnetite.
The Napak volcano holds an important place in carbonatite studies as it was the first locality at which the relationship between intrusive carbonatite and volcanism was first demonstrated (King, 1949).
This plug comprises a central intrusion of carbonatite 400 m in diameter surrounded by an 800 m wide collar of ijolitic rocks. The carbonatite forms Lolekek Hill but the surrounding ijolites are only discontinuously exposed away from the hill.
The Kadam volcano has a diameter of some 35-40 km but its southern margin is not clear because of interdigitation with products of Mount Elgon (No. 24).
Kokipie Hill lying on the border with Kenya is the only significant remnant of a volcanic cone that was fed from a heart-shaped vent lying to the northwest.
Mount Elgon is the largest of the group of Tertiary volcanoes of eastern Uganda, although nearly half of the volcano lies in Kenya. Its height is over 4000 m and the total area covered by volcanic rocks is in excess of 3000 m2.