Some of the grains weather to a pale green colour. In thin section, quartz is the major grain type (~50%) with some microcline (~5%) and some rock fragments (~1%) all in a fine matrix which consists of quartz and/or feldspar, mica and some calcite cement. The majority of the grains have a red-brown altered rim. The rock fragments are possibly reworked sediments" (p. 13).

Lettergesh

Analysis by Farrell indicates that this formation is primarily comprised of quartz-rich sandstones, mudstones and siltstones. This authority adds that, "The sandstone should more accurately be called a greywacke and it is the most common rocktype. The formation has a total thickness of about 1096m including the thickness of the two microgranodiorite bodies which intrude it. At the base of the formation (L754 610 and surrounds) there is a body of conglomerate which is part of the Gowlaun member defined by Laird and McKerrow (1970)....
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