About the author
Virginia Clark was a pseudonym used by Patsey Gray, about whom you can find more information here.
Finding the book
The book is not hugely common, and pricing is variable.
Links and sources
Terri A. Wear: Horse Stories, an Annotated Bibliography, Scarecrow Press, 1987
Bibliography (horse books only)
The Mysterious Buckskin
Macmillan, New York, 1960, 164 pp
Ann and Ken take three dude riders and their horses on a long trail ride. They have a buckskin horse, which Ann thinks looks just like her Frosty, stolen a couple of years earlier. Ken was actually accused of stealing the horse.