thesisThe author is deelpy indebted to Dr. Norman C. Williams, at whose suggestion the problem was undertaken, for his invaluable counsel in the field and in the preparation of the manuscript; to Dr. A. J. Eardley for much valuable information and for his aid in editing the manuscript ; to Dr. W. L. Stokes for helping edit the manuscript and for identifying the fossil collection; and finally to Mr. W. J. Wood for his help in measuring the stratigraphic section
