Baird, S. F. 1859 "1857". Report upon reptiles collected on the survey. Reports of ... E.G. Beckwith ... Upon Explorations and Surveys to Ascertain the Most Practicable .... Route for a Railroad from the Mississippi River to the Pacific Ocean, Near the Thirty-eighth and Thirty-ninth Parallel ... and Near the Forty-first Parallel. Volume 10, Part 4, No. 4: 9–13. Washington, D.C.