DALLAS, TX.- When Crystal Murray won a $10 box lot of 19th century sheet music at a small Indiana estate auction in the mid-1980s, she thought it was the perfect discovery for her children who were learning to play the piano. Besides finding new songs for her children, she also discovered a rare, early map of Texas and related historical letter and documents Texas historians say could sell for as much as $8,000 March 12 at Heritage Auctions.

"I saw the box of sheet music at an auction in Seymour, Indiana, and my children at the time were taking up piano lessons," Murray said. "All of the music was from within that period of the late 1800s and we discovered the book with the map in the box. We thought it was interesting and we always kept the letters with the map."

Murray discovered an 1853 edition of J. De Cordova's Map of Texas — a large format lithograph map, measuring 32-3/4" by 34-3/4", elegantly colored by hand, showing counties, cities and towns, roads, rivers, and Indian villages. The map features an elliptical inset at lower right of the southwestern United States and Mexico and a second inset along the left lists land districts and their respective counties.

"This map was first issued in 1849, but what makes this example truly unique is that it appears to be the copy owned by James M. Manning, the surveyor who made crucial changes for the 1853 edition," said Sandra Palomino, Director of Historical Manuscripts at Heritage Auctions. "Manning was Deputy District Surveyor for Corpus Christi in 1852 and the front pastedown of the book holding the map is signed: "James M. Manning's map / corrected for its Author by said Manning."

Also present with the map is James Manning's military appointment to the rank of corporal in the 5th Regiment, 8th Brigade, and 9th Division of Infantry of the New York state militia.

But the discoveries didn't stop there. Gently folded inside the map's two, leather-bound covers is a letter from De Cordova to Manning, following up on a few changes to the map and ensuring Manning would be paid for his work. The letter by itself is estimated to sell for $800, Palomino said.

Both the map and the letter, along with 280 lots related to Texas history, will be offered in Heritage Auctions' annual Texana Grand Format Auction March 12. The map and letter will be on display at Heritage's headquarters on March 11 at 3500 Maple Ave. in Dallas. Additional lots of Texas history will also be on display during the Texas State Historical Association's 120th Annual Meeting and Conference, March 3-5 in Irving, Texas.