In this paper attention is called to the need of co-operative work among investigators in the different fields of science. Reference is made to several bulletins and papers which have already been published by the chemists of the United States Geological Survey, by the physicists of the geophysical laboratory, and by other scientists, throwing light on many problems in geology which heretofore were obscure. The necessity for further work upon border problems, already under investigation, and upon many other problems which need solution, is emphasized
