The Collaborative International Dictionary of English v.0.48:

Sherryvallies \Sher"ry*val`lies\, n. pl. [Cf. Sp. zaraquelles
   wide breeches or overalls.]
   Trousers or overalls of thick cloth or leather, buttoned on
   the outside of each leg, and generally worn to protect other
   trousers when riding on horseback. [Local, U.S.] --Bartlett.
   [1913 Webster]