MR. E. HOWARD ADYE, as Director of the Geological Survey of Navánagar, has written a memoir of 262 pages on the economic geology of the State. A coloured lithological map, on the scale of one inch to four miles, is bound up in sections with the volume, and numerous photographic plates of rock-sections and a few landscapes illustrate the text. The rock-slices have been selected with the care that might be expected from Mr, Adye's previous work (see NATURE, vol. lxxvii., p. 125), and a system of lettering indicates the various mineral constituents. The production of this handsome and well-bound memoir by the Government of a native State in India renders the portrait of the Maharaja, Jam Shri Ranjitsinhji, distinctly welcome as a frontispiece.