This is Sheet 231 and covers the area from Ystradgynlais Colliery in the West to Merthyr Tydfil in the East and from Fforest Fawr in the North to Aberdare in the South. Surveyed in 1867 - 85 and Published by Major General Sir C. W. Wilson K.C.B. F.R.S., R.F. Director General. 1894. Revised in 1907 and Published by Colonel S.C.N. Grant 1909. Railways inserted to 1914. Scale of One Inch to One Statute Mile.
Approx 49cms by 34cms.
