Cylchgronau Cymru

change of name? The Mochdre Brook itself did not bear that name in Silvan Evans's list: there it is called Dulas. The more documentation there is for a particular stream, the more evidence is available of changes of name.8 The names which appear to survive are those of streams which have some importance as regards size or connections. A small stream at one period may have been noteworthy because it marked the bounds of two territorial divisions but once it lost its role in determining ownership and awards of land it became insignificant and of concern only to people in the immediate vicinity instead of as before to princes and prelates whose provenance and authority were determined by humble rivulets. The student, who, because of the frequent occurrence in charters and documents of names no longer in use, tends to think that change of name is the rule and not the exception for a stream, should not exaggerate the impermanence and mutability and forget that there has always been at work a powerful tendency to preserve and conserve. This acts as a salutary and necessary control: without it names would be changed according to the whims and fancies of individuals as often happens to the names of houses in suburbia. Bearing these two opposing tendencies in mind, it is illuminating to ascertain what has happened to the stream names cited in the earliest documents which contain the names of Montgomershire streams. I refer to the charters of the abbey of Strata Marcella (v. Bibliogra- phy), Ystrad Marchell, which was built around 1172 a short distance down stream from Welshpool. They record the award and sale of lands to the monastic foundation. The fabric of the abbey has practically completely disappeared but fortunately the number of charters still extant is unusually large for a foundation of that period. The charter names in the Severn basin may be sorted out geographically into four groups.9. 1. near the Abbey: Bele 2. in the Efyrnwy basin: Cynllaith, Dolau Gwynion, Efyrnwy, y Fagl, Llanwddyn. 3. in the Banw basin: Bolo, Cannon, Derwen, Efyrnwy, Lledwern, Marchno (?), Nant yr Eira, Nodwydd, Ysguthan. 4. mainly in Arwystli: Bacho, Buga, Bretwen, Dyfngwm, Ffinnant, Garth Branddu, Hanog, Pwll Llydan, Rhiw. The notes will indicate to what extent the following names are in use today for the same water courses, Bacho, Buga, Bele, Cynllaith, Cannon, Dolaugwynion, Efyrnwy, Fagl, Hanog, Llwyd, Nant yr Eira, Nodwydd, Rhiw and Ysguthan. Pwll Llydan and Llanwddyn are recorded as having been used for portions of Afon Garno and Efyrnwy Dyfngwm is well documented. As regards the remainder, Bolo, Bretwen, Derwen, Ffinnant, Lledwern and Marchno, there are some probable and some very tentative identifications in the notes. Some understanding of the results over the centuries of the two opposing tendencies which determine the fate of place-names, the conservative and reformative, spelling survival for some and extinction for others, can be obtained by studying the stream names in a district where happily names have been recorded fairly extensively and in different periods. Carno is such a district. Some of the streams in the vicinity are cited in the Strata Marcella Charters, in a 1608 law suit concerning boundaries (v. Mont Coll XXII, 215) and on early nineteenth century maps relating to enclosures and and tithes. (v. Mont Coll LXII, 211 et seq.). v'Small streams often have names as impermanent as the names of fields." Wainwright, Archaeology and Place Names, London, 1962, .58. 'Several streams in the Dyfi basin are cited in the Charters. Most of them are easily identified.