What is rarely mentioned is the mixture of flat and round stone together. I believe that this is infinitely more difficult! Trying to bring round stone up to a position whereby a flat stone can look acceptable around it is very tricky. It's something that is possible only with years of experience and years of walling with difficult stone. While this wall can be said to have a few minor issues the creativity of Andrew Loudon in this bit of work is highly evidenced. I first saw him combining this material in Cumbria on a project and marvelled at his ability to blend the two. It was only later in my career that the opportunity to combine the two materials came up. We tend to end up with either of the two but rarely combined here in Ontario.