In the massive tuffs, vitric to crysto-vitric varieties show delicately shaped glass shards and broken phenocrysts of euhedral quartz, plagioclase, muscovite, orthoclase, zircon and ilmenite.
Medium-grained sandstones (protoquartzite) contain quite well-rounded quartz grains, quartzite lithoclasts, muscovite, plagioclase (rare) and bioclasts, especially echinoderm plates, cemented by calcite spar.
Structural formulae were calculated on the basis of 12 oxygens for garnet, 8 for plagioclase, 22 for biotite and muscovite and 27 for staurolite.
The granite is made up of plagioclase, alkali feldspar and quartz with minor biotite and muscovite and accessory apatite, zircon and opaque minerals.
The lamination is defined by alternations of quartz-rich laminae and chlorite-muscovite rich bands, and appears to be laterally continuous on the scale of an outcrop.
However, unless careful preliminary investigations are made, weak reflections, perhaps indicative of cation ordering as in rose muscovite and ephesite, may be missed.
The rock fragments are mainly rhyolite, granite, and spherulite of rhyolite, with very small amounts of muscovite-quartz schist and hornfels exhibiting a granoblastic texture.
Grains of quartz and mica (mostly muscovite) occur dispersed or parallel to bedding planes.
