- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
A small mass consisting of three intrusions of fine-textured acid rocks occurs within the basaltic agglomerates of the Kilchrist vent of Tertiary age. One of the intrusions comprises flow-layered rhyolite and ignimbrite. It is thought that the rock-types represent two distinctive eruptive waves. A form of ovoidal structure not seen elsewhere in the Kilchrist area occurs in another rhyolite intrusion.