Chelsea Riding. The top (opening) is a half-inch bigger on the Molly than on the Chelsea, but the Molly's midcalf is 0.8" smaller around, and the ankle measurement is the same for these two sleek, unfussy designs that -- it's safe to say -- are not going out of style anytime soon.
If you're between half-sizes, I'd recommend going with the larger. I usually take a 7.5 but occasionally an 8, and though good leather will stretch somewhat, I think in the Molly I'd be better off with an 8. With free shipping sites, of course, you can always get both sizes and send one back.
Calf slimness: ****/5
Find it at:
Amazon (four colors; as of mid October 2015, over 60% off in some size/color combos)