Apart from The Screes, Whin Rigg has another fine geological feature in Greathall Gill. This is a granite ravine which rises up the fell from where the River Irt flows out of Wast Water to the 400 metre mark on the fell to the south west of the summit. The lower section of the ravine in steep sided and wooded and support a range of mosses, ferns and herbs including Common wood sorrel, Chrysosplenium oppositifolium (opposite leaved golden saxifrage) and great wood rush.