An altered and highly permeable crystal lithic tuff
unit contains disseminations of silver bearing minerals and domains with broadly spaced stockwork veinlets.
porphyritic igneous rock, lithic tuff
, and metamorphic rock).
The Bayswater Formation comprises a sequence of rhyolitic to dacitic, lithic to lithic-crystal lapilli tuff and subordinate andesitic lithic tuff
, thin-bedded tuffaceous siltstone and micaceous phyllite, and constitutes one of several steeply-dipping, northwest-younging volcanic sequences within the
Similar alteration occurs in the overlying lithic tuff
but is limited to structures.
In this area an altered and highly permeable crystal lithic tuff
unit contains disseminations of silver bearing minerals and broadly spaced stockwork veinlets.
The sampled horizon is a massive, dark grey, fine-grained, crystal tuff that is interbedded with coarse, lithic tuff
containing mafic and felsic fragments.
It includes felsic crystal and lithic tuff
, flow-banded rhyolite, andesitic lithic tuff
, laminated siltstone, and banded marble.
Basaltic fragments are abundant in the coarse lithic tuff
at Gorhams Bluff where they underlie an amygdaloidal basalt flow near the top of the section.