9 books
Report of Progress Volume 6
Report of Progress Volume 2
Report of Progress Volume 5
A Dictionary of the Fossils of Pennsylvania and Neighboring States Named in the Reports and Catalogues of the Survey
A Dictionary of the Fossils of Pennsylvania and Neighboring States Named in the Reports and Catalogues of the Survey Volume 2
A Dictionary of the Fossils of Pennsylvania and Neighboring States Named in the Reports and Catalogues of the Survey Volume 3
A Dictionary of the Fossils of Pennsylvania and Neighboring States Named in the Reports and Catalogues of the Survey Volume 1
Report of Progress Volume 1
Report of Progress (Volume 1874)