THE literature of American geology increases at an almost overwhelming rate. We have just received three large volumes containing 2053 pages of letterpress, including Part ii. of the Eighteenth Annual Report of the Survey for 1896–97, being papers chiefly of a theoretical nature; and Part v., the Mineral Resources, in two volumes. We have already called attention in NATURE for May 4 to some of the papers contained in Part ii., of which we received advance copies; these were on “The Triassic Formation of Connecticut,” by W. M. Davis, with coloured maps and sections; on the “Geology of the Edwards Plateau and Rio Grande Plain adjacent to Austin and San Antonio, Texas, with reference to the occurrence of underground waters,” by R. T. Hill and T. WT. Vaughan; and “A Table of the North American Tertiary Horizons, correlated with one another and with those of Western Europe, with annotations,” by Mr. William H. Dall.