BY N. H. DARTON
This list includes data collected during the past fifteen years by the author and his associates in various portions of the United States. Several hundred observations have been made in deep borings with a self-recording thermometer o f special type. All other available data have been compiled to make the list as complete as possible. The rate of temperature increase has been found to be very variable, but in places there is a marked relation to geologic features.
BY RICHARD B. HICE
Of the whole Allegheny series in western Pennsylvania, no horizon is more regular and continuous than the Lower Kittanning coal; indeed, with its ac companying clay, it is one of the best keys of the series. While there are many changes and local variations in the sandstones . . .