Definition from Wiktionary, the free dictionary
sherryvallies (plural only)
- (historical) Thick loose riding-trousers, fastened on the outside of each leg.
- 1860: Many years ago, when the facilities for travelling were not as great as now, and when journeys were made on horseback, sherryvallies were indispensable to the traveller. — John Russell Bartlett, Dictionary of Americanisms (Brown Little 1860, p. 399)