This is Number 1 of the series of correlation charts of North American sedimentary formations in preparation by the Committee on Stratigraphy of the National Research Council, with the co-operation of other American stratigraphers (Dunbar, Carl O., et al., 1942). The Cambrian Subcommittee of that Committee records here its thanks for the assistance which it has received from these friends, who have generously supplied much invaluable unpublished information.
The Cambrian chart has been especially difficult to prepare because of the incompleteness of our knowledge of the stratigraphy and faunas of the Cambrian rocks of some parts of this continent. To make it even reasonably complete and accurate it has been necessary for some of the members of the Cambrian Subcommittee to spend many months in field and laboratory work on previously little known sections and unstudied faunas. Some of this work has been made possible by generous grants from the . . .