that were increasingly at risk from development: they were defined as "all types of ancient structures which are no longer capable of active use", a definition that allowed the inclusion of certain industrial monuments but excluded churches and mansions. A further advantage of this new project was that priority could be given to two counties that so far had no inventories. Yet only two of these new lists were issued: the first for Cardiganshire in 1970 and the second in 1973 for the "Early Monuments" of Monmouthshire. Excavated and recorded sites A second experiment capitalised on the Commission's growing archive of excavated and recorded sites. In 1971 it published what it saw as "the first of a series of reports by which... the National Monuments Record of Wales hopes to provide accounts of the major field monuments for which no adequate descriptions exist". This was a detailed survey of the hut settlement on Gateholm Island, Pembrokeshire. The commissioners turned for another development to one of the senior investigators, Peter Smith, who had been studying over a number of years the historical and stylistic evolution of house types in Wales. The resulting book, Houses of the Welsh Countryside, which was brought out at the end of 1975 to coincide with Architectural Heritage Year, demonstrated that the inventories could take yet another form, as national studies of a topic. Smith's book, a contribution of European importance to the history of domestic architecture, was published to great acclaim, and an expanded edition appeared in 1988. Excavation was a prominent activity of the Royal Commission during Hogg's period as secretary, reflecting his own interests and the dearth of other organisations to carry them out. For example, between 1957 and 1960 staff were diverted to the rescue excavation of the Roman fort at Pen Llystyn, Caernarfonshire, and in 1962 Hogg directed rescue excavations associated with a hydro-electric scheme on the site of Bronze Age cairns at Aber Camddwr, Cardiganshire. For several seasons in the 1960s, L. A. S. Butler conducted excavations in medieval Conwy, including in the vicarage garden where a medieval building had possibly been destroyed during Owain Glyn Dŵr's revolt. Other excavations at this time were part of the inventory programme for Glamorgan, such as at Harding's Down in Gower, where a rampart section was cut and an entrance and two hut platforms were revealed in an Iron Age hillfort. The Commission made