On the relations of the Niagara and Lower Helderberg formations, and their geographical distributions in the United States and Canada
By: by James Hall.
Contributors: Worthen, A. H. 1813-1888.; American Association for the Advancement of Science.
Series: CIHM/ICMH Microfiche series -- no. 34436
Publisher: s.n.]
Published: 1982
Place of publication: [Salem, Mass.?
Language: eng
Format: Microform
Number of pages: 11
Subjects: Geology, Stratigraphic -- Paleozoic.
Notes: Caption title.

"From the Proceedings of the American Association for the Advancement of Science, Portland Meeting, August, 1873."

Criticism of A.H. Worthen's article, Remarks on the relative age of the Niagara and so-called Lower Helderberg groups.

Filmed from a copy of the original publication held by the Library of Congress, Photoduplication Service. Ottawa : Canadian Institute for Historical Microreproductions, 1982.