A description of a device for locating points on a contour map and how it has been used in geologic mapping.

From the reviews: "...is a "must" for serious field novices, and for seasoned middle-career and senior practitioners in hydrogeology, mainly those people who answer a calling to offer honest and accurate hydrogeological approximations and findings. Any engineering geologist or groundwater geologist who claims capability as a "Hydrogeologist" should own this book and submit it to highlighting and page tabbing. Of course, the same goes for those who practice in karst terranes, as author LaMoreaux is one of the pioneers in this field, worldwide..." (Allen W. Hatheway)

February issue includes Appendix entitled Directory of United States Government periodicals and subscription publications; September issue includes List of depository libraries; June and December issues include semiannual index.

1919/28 cumulation includes material previously issued in the 1919/20-1935/36 issues and also material not published separately for 1927/28. 1929/39 cumulation includes material previously issued in the 1929/30-1935/36 issues and also material for 1937-39 not published separately.