@book{bhlitem48814, title = {The earth as modified by human action / by George P. Marsh }, volume = {1874 edition}, copyright = {Public domain. The BHL considers that this work is no longer under copyright protection.}, url = {https://www.biodiversitylibrary.org/item/48814}, note = {https://www.biodiversitylibrary.org/bibliography/53722}, publisher = {New York, Scribner, Armstrong & Co, 1874}, author = {Marsh, George Perkins,}, year = {1907}, pages = {690}, keywords = {Human geography|Physical geography|}, }