I. Introduction Although the Purbeck Beds of the Vale of Wardour have been noticed by many observers, and portions of them have been described by many writers from the time of Fitton downwards, no complete description of the whole series has yet been attempted, and a connected account of the Wiltshire Purbecks seems therefore to be a desideratum in geological literature. Fitton gave some account of them in his classical memoir ‘On the Strata between the Chalk and the Oxford Oolite,’ published in 1836, mentioning quarries at Dallard's Farm, Dashlet, Chicksgrove Mill, and Wockley; but since his time the Wockley quarry has been cut back, so as to expose the beds which were then only visible at Chicksgrove. He made no attempt to establish any succession, and thought the total thickness of the series was not more than 60 feet. The Rev. P. B. Brodie, in 1845, published a little book entitled ‘ A History of the Fossil Insects in the Secondary Rocks of England’ in which he gave some description of the Purbect Beds of Land’ in which he gave some description of the Purbeck Beds of the Vale of Wardour, and especially of two beds of limestone, one of which he called the ‘Isopod Limestone,’ because it contained Archœniscus , and the other the ‘Insect Limestone,’ from the abundance of insect-remains in it. Unfortunately, his reference to localities was not very explicit, but it is certain that the quarries “not far from the village of Dinton,” where he saw