This sort of deco school/college belt buckle was popular in the 1920's-30's...up to the 50's they were still around, but I think yours is an earlier one. Some can found with a patent date of May 29, 1923.
A couple of the big names that made them are Giant Grip, Kinney Co., and T.V.Allen (which I'd bet yours is). But here's some other examples: http://www.google.com/search?sclien...ws..29.19.3669...30i10k1j0i67k1j0.Apo46hRMv2g