In area they are mainly concerned with the parishes on both sides of the Merioneth-Caernarvonshire border, Bob's own homeland. Ardudwy is pretty thoroughly done, with especial attention to the shipping activities of old Barmouth; so is the Llanfachreth-Dolgellau district, the uplands of Dolwyddelan and Penmachno. Bob was much interested in Hugh Owen, the Puritan of Bronyclydwr and his descendants in the Dysynni Valley; also in the family of Howell Hughes of Brynrodyn in Cynfal (H.H. figures in the letters of Morgan Llwyd). Several Anglesey wills have been analysed, particularly those of Aberffraw and Llangadwaladr, from which parishes his ancestors on the mother's side came.
If carefully and scientifically studied these wills and inventories present first-hand knowledge of country customs and changes in agricultural methods; of course, they are even more helpful in tracing family pedigrees.