The Quarterly Journal of the Geological Society of London, Volumen 102

amphibole analyses anomaly appear Bache Peninsula banded basic basin beds Belhelvie biotite Cambrian Cape Carboniferous chambers chemical Coal Measures composition constituents cranidium deposits desilication displacement dolerite east eastern erosion evidence faunas feet felspar felspathization folding foraminifera formation fossils genus Geol geological geologists glabella Glen Fault Goldfield granite gravity greenstone Grits grunerite highlands horizon hornfels hornfelses igneous rocks inclusions intrusion jasper bars Jurassic Karroo laccolith Lake later limestone Lower magnetite marine mass megalosphere metamorphism migmatite miles milligals minerals Miocene Miocene peneplain non-marine north-west occur Old Red Sandstone olivine olivine-gabbros Ophthalmidium Ordovician original peneplain plagioclase plateau Poulsen present probably pyroxene quartz region represented ridge Rift scarps schists seams sedimentary sediments shales siliceous Silurian similar species specimens spore types spores stage strata structure surface Surv thickness troctolites trough Upper Valley variation Welfield western xenolith zone