 His interest in and production of concept art began under the mentorship of character designer Mark "Crash" McCreery, and Marshall later became well-known as a paleoartist by working on a number of new dinosaur discoveries and press releases with paleontologist Paul Sereno at the University of Chicago.He is based in Boise, Idaho.In interview with Steve White, Marshall describes his introduction to the art of dinosaur reconstruction through the 1966 film "One Million Years B.C.