Port Isabel & Rio Grande Valley Railway Company (Tex.), Map Showing Port Isabel in 1934.     Source: Geological Survey (U.S.), 1934. Texas, Port Isabel quadrangle. 1:31680 series. [Washington, D.C.]: U.S. Geological Survey.           << Map Index             Information and images were digitized and proofread from the original source documents by Murry Hammond. Contact Murry for all corrections, additions, and contributions of new material.