This paper is based on observations, made chiefly during field research, and detailed mapping of the Big Blue series in the north-central part of Kansas in Marshall, Washington, Clay, and Dickinson counties in 1932 for the State Geological Survey of Kansas. Various points of cyclic analysis and problems of environments of Late Paleozoic sedimentation in the northern Mid-Continent have been discussed with Dr. R. C. Moore and Dr. N. D. Newell, of the University of Kansas. The manuscript has been read by Dr. Moore and Dr. W. H. Twenhofel, whose criticism and suggestions are gratefully acknowledged.
The application of the theory of cyclic sedimentation to the Big Blue series was reported to the Paleontological Society in 1933,1 and its significance in stratigraphic classification of Late Paleozoic rocks in Kansas was discussed jointly with R. C. Moore at that time.2 An attempt to estimate the depth of deposition . . .