John is correct. The Marshes & Shepherd is a 'Tapered Grind' blade and they are rather rare. I have several and they are some of my favorite shavers. Here are a couple of threads for you to peruse about these type blade profiles:
The W&B in the second link is gorgeous, I love the spine. I have a couple of razors like this myself. The Elliot Damascus Steel is a particularly fine shaver.