Dan Q posted a note for GC23N8B Alphabet Series - C

This checkin to GC23N8B Alphabet Series - C reflects a geocaching.com log entry. See more of Dan's cache logs.

I'll go hunt for this tomorrow, probably (I'm very familiar with the area in question: it's right next to where I work), but based on the map this cache is by the River Rheidol, not the Ystwyth, which (confusingly) is actually a little further South. Just thought you ought to know!