Summary of site:
The Tullyard Conglomerate Member stratotype, the site which gives the member its name and defines its features, forms both banks of this deeply cut, east-flowing stream. Its estimated thickness of between 4 and 5 m is calculated from a number of discontinuous outcrops including the waterfall to the west.
The rock fragments in the conglomerate are small, generally less than 5 mm across, although a few reach 1.5 cm. They are mostly of white quartz (a few are pink) in lime-rich sandstones. All grains are well rounded indicating a long history in turbulent water.
The conglomerate is important because it marks the base of the Bin Mountain Sandstone Formation, an early Carboniferous rock with fossils giving an age in the Chadian stage, around 345 million years ago.
All stratotypes are essential markers in the geological history of their areas and this one provides useful information of the environment at the start of Bin Mountain Sandstone times. It should be preserved.