Note 36 — Chapter IV
Reading edition
1. Holmes, W. H. Fossil Forests of the Volcanic Tertiary Formations of the Yellowstone National Park. Ann. Rep. Geol. and Geogr. Surv. (U.S.A.), 1878, Pt. II. p. 47.
2. Knowlton, F. H. Fossil Flora of the Yellowstone National Park. Monograph 32, U. S. Geol. Survey, Pt. II. 1899.