Looking for angular/sharp sand for cob oven project - pronto!

Carlyn, daughter of Sharon Yandle here, in frantic search for enough sharp sand to build a cob oven. (A few five-gallen bucketfuls?) Frantic because I've got a crew coming over next Monday ready to build but my search has come up empty. 

Any leads greatly appreciated. We can come pick up as soon as the morning of Monday, June 22.