Summary of site:
This site is the stratotype of the Rushindoo Oolite Member of the Bin Mountain Sandstone which is of Carboniferous age. A geological formation is named and defined from a locality where it is best or most typically developed. Such localities are called stratotypes and normally bear a name relating to the local geography, in this case the townland.
The Rushindoo Oolite is a local variant within the Bin Mountain Sandstone. In this small quarry 3.5 m of pale grey to fawn medium-grained oolites, some sandy, occur with thin lime-rich sandstones. Oolites are made up of small spherical particles of calcium carbonate, each formed around a solid nucleus such as a shell fragment or sand grain. They are formed in agitated water saturated with lime which coats the constantly rolling nuclei. Neither the top nor the base of the member is seen in the quarry but it is believed to be around 6 m thick.
The Bin Mountain Sandstone was formed along or slightly behind a shallow shore at a time of fluctuating sea level. Trace fossils are indications of animal activity and two are common here, Pelecypodichnus and Skolithos, indentations made by bivalve molluscs and worm burrows respectively. Both indicate a shallow inshore environment. Scattered ooids (individual oolite particles) are common throughout the Bin Mountain Sandstone so it is not surprising that in one area conditions favoured the creation of predominantly oolitic limestones as at Rushindoo.
As the stratotype of an important member of the Bin Mountain Sandstone, this small quarry is an important element in our understanding of events in the early Carboniferous and should be protected and conserved.