Abstract
ONE of the most difficult problems with, which American geologists and palaeontologists are confronted is the correlation of the Later Cretaceous and Lower Tertiary strata in the different regions of the United States. The Professional Paper by Messrs. Lee and Knowlton is concerned with some of the Cretaceous and Tertiary rocks in the Rocky Mountains region of Colorado and New Mexico. A considerable area in the interior of North America was occupied by a Cretaceous sea, and it was part of this area which was afterwards uplifted as the Rocky Mountains chain. This crust-folding was followed by the deposition of plant-bearing Tertiary strata. The Raton. Mesa region is rich in coal-bearing beds containing a large number of flowering plants, with a few twigs of conifers and fragments of sterile fern-fronds. The flowering plants are, unfortunately, represented almost exclusively by detached leaves.
Article PDF
Rights and permissions
About this article
Cite this article
SEWARD, A. The Cretadeous-Tertiary Boundary in North America1. Nature 107, 282–283 (1921). https://doi.org/10.1038/107282b0
Issue Date:
DOI: https://doi.org/10.1038/107282b0