US Geological Survey


Date of this Version



The Journal of Geology, Vol. 37, No. 1 (Jan. - Feb., 1929), pp. 47-63


The conclusion drawn by Professor E. B. Branson in a recent paper on the "Red Beds" of the Rocky Mountain region that parts of these beds are marine is considered likely. The conclusion that there exists no basis for subdivision of the beds is not accepted, and a division of the Mesozoic part into Lower Triassic, Upper Triassic, and Jurassic units is advocated. The conclusion that no eolian deposits are present likewise is not accepted, and the interpretation of important parts of the Jurassic unit as eolian is advocated. Disagreement is expressed with much of Professor Branson's correlation table, and a substitute is offered. His paleographic map is considered invalid because based on erroneous correlations and interpretations of conditions.