Map of the United States showing the Principal Botanical Divisions by Thomas C. Porter, A.M., Professor of Botany in Lafayette College, Easton, Pa. Entered ... 1873 by O.W. Gray: Gray's Atlas Of The United States, With General Maps Of The World. Accompanied By Descriptions Geographical, Historical, Scientific and Statistical. By O.W. Gray, Civil And Topographical Engineer, No. 10 North Fifth Street, Philadelphia. Published By Stedman, Brown & Lyon, No. 10 North Fifth Street, Philadelphia. 1873. (on verso) Entered ... 1873, by O.W. Gray ... Washington