In reply to pec:
> I don't but I'd be interested to find out more.
Hounds Head Buttress was a crack cimb at Tremadog. I forget the grade but IIRC it was about Severe. I first climbed it in the early 1960s. I repeated the climb a few years later and the crack had become a chimney!
Caernarfanshire County Council became concerned at the obvious ongoing movement and instability and in the mid 1960s (I don't recall the exact date) they decided that the risk of collapse, which would have resulted in it spilling onto the road below, was becoming too serious, and they dynamited it.
I can't find much about it on Google now, but it was reported in the press and climbing magazines at the time.