I think it looks more like the I in Iron Bridge (2 lines below in original) than anything else
There are no uprights or tails, so we've probably got a lot of n, w, m, r, e etc. Could be any where in Wales really

Does anyone know where the old border was between Montgomeryshire and Denbighshire? That might narrow it down a bit as he seems to have crossed over between 1851 & 1861!
Linda