THE third annual report of this survey of Great Britain shows a growing rate of progress towards the completion of the work. With a total of 15,000 finished six-inch sheets, three-quarters of the field work has now been accomplished. Thirty-six counties are completed and twenty-five more are nearly complete. Parts of Norfolk, West Suffolk, the West Riding, Westmoreland, Cornwall, Carmarthen and Somerset still call for more workers. In southern Scotland there are large areas still to be done. A year ago two sheets, reduced to a one-inch scale from the six-inch sheets, were published by the Ordnance Survey. Eight sheets in all have now been published and four more are in the press. Work is proceeding on the reduction and preparation for press of twenty-nine further sheets. It is proposed to publish a series of explanatory memoirs on certain of the sheets and several of these are now in preparation. The report summarises the extent of work done in each county and contains a map of Great Britain showing completed areas.