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DALLAS (CBSDFW.COM/AP) – A rare early map of Texas and another historical document discovered in a box of sheet music purchased for $10 at an Indiana estate auction in the 1980s could sell for as much as $7,000 at auction.

Heritage Auctions is offering the items Saturday in Dallas.

Crystal Murray says in a Heritage news release she was intrigued by the sheet music because her children took piano lessons at the time.

Heritage’s Sandra Palomino says the 1853 edition of J. De Cordova’s map of Texas appears to have been the copy owned by James M. Manning, the surveyor who made “crucial changes” for the map’s 1853 edition. A signature says the map was his.

A document showing Manning’s military appointment to the rank of corporal will be sold with the map.

Officials with the auction house say he map was first issued in 1849, and revised the following year. The 1853 up for auction this weekend had further revisions.

It is said that Sam Houston, during a speech on the floor of the Senate, praised the map [the 1849 edition] as being “the most correct and authentic map of Texas ever compiled.”

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