The rocks are almost entirely known from drill core and only exposed in outcrop near Spavinaw, Mayes County, Oklahoma and parts of the Saint Francois Mountains in Washington County, Missouri.
The board, in turn, hired J. H. Trammell to perform as the engineering contractor to plan the Spavinaw project, with W. R. Holway as his assistant.
They had decided to build a reservoir on Spavinaw Creek, a tributary of the Verdigris River, over fifty miles northeast of Tulsa.