The petrology of the Mid-Jurassic sands in the south-west of England has been described both by Professor P. G. H. Boswell and Dr. J. G. A. Skerl. Professor Boswell has dealt with the Toarcian-Aalenian sands from various localities between Cheltenham and the Dorset coast; Dr. Skerl with certain Bajocian and Bathonian beds in the North Cotteswolds. The present paper gives some account of the lithology and terrigenous minerals of the oolitic limestones of Dundry, an area approximately midway between the Cheltenham region and the south coast. Dundry Hill is an isolated patch of Oolite some 8 miles west of the Bath Hills, and Dundry village, which stands on its crest, is 5 miles south of Bristol. The geology and palaeontology of the area have received the attention of many geologists from the time of Conybeare and Phillips, but here only the work of S. S. Buckman and E. Wilson need be referred to, since these authors fully review the previous literature. Buckman and Wilson described the rocks in great detail, and their classification of the strata has been utilized here.