Scientific Serials

Abstract

American Journal of Science, June.—Fossil faunas and their use in correlating geological formations, by Henry S. Williams. It is shown that the plan usually followed of classifying geological formations in time by means of a comparison of one predominant fossil is wanting in accuracy. Very many single species, the range of which has been established by thorough study of the successive formations in which they occur, range through a third, and often a half, of one of the standard geological systems. A second reason for not resting implicit confidence on this method of correlation is the frequently observed fact that parts of the geological column of different sections, which upon satisfactory stratigraphic grounds are known to be strati-graphically equivalent, contain different fossils.—Studies of the Kocene mammalia in the Marsh collection, Peabody Museum, by J. L. Wortman. The present instalment of this series contains detailed descriptions of Sinopa rapax and Sinopa agilis.—The transmission of sound through solid walls, by F. L. Tufts. The rigidity of the material was found to be the main factor in determining the intensity of the sound transmitted from the air on one side to the air on the other, the only other factor possessing any influence being the mass.—A new gauge for the measurement of small pressures, by E. W. Morley and C. F. Brush. A description of a form of differential mercury pressure gauge resembling in principle that recently described by Lord Rayleigh. Two modes of reading are given; in the second method a reading can be taken in ten seconds. With suitably mounted instruments pressures may be read with a mean error of not more than a ten-thousandth of a millimetre.—On a hitherto untried form of mounting either equatorial or azimuth, for a telescope of exceptional size, either reflector or refractor, in which telescope, observing floor and dome are combined in one, by D. P. Todd.—On the occurrence of uranophane in Georgia, by T. L. Watson.—The internal structure of cliftonite, by J. M. Davison. The view of Fletcher that this form of crystallised carbon is a pseudomorph after pyrite is not confirmed by these experiments.