WASHINGTON, _August 26, 1850_.
_To the Senate of the United States_:
I have the honor to inclose herewith a letter just received from the
Secretary of War, transmitting a communication from the Colonel of
the Corps of Topographical Engineers, with accompanying papers, which
he requests may be taken as a supplement to the "report and map of
Lieutenant J.D. Webster, Corps of Topographical Engineers, of a survey
of the Gulf coast at the mouth of the Rio Grande and its vicinity,"
called for by a resolution of the Senate of the 1st of July last.