Certain amygdaloidal tholeiitic rocks and associated volcanic breccias are intrusive into the Cuillin gabbro (sensu lato) and are not xenolithic as Harker believed. Six tholeiites have been analysed and their compositions compared with the non-porphyritic central magma type of Mull. It is postulated that the ultrabasic rocks close to some tholeiitic intrusions were contaminated by the tholeiitic magma.

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