ADVERTISEMENT. VII 



138. Artesian-well Prospects in the Atlantic Coastal Plain Kogion, by N. H. Darton. 1896. 8'-'. 228 

 pp. 19 pi. Price 20 cents. . 



139. Geology of the Castle Mountain Mining District, Montana, by VV. H. Weed and L. V. Pirsson. 

 1896. 80. 164 pp. 17 i>l. Price 15 cents. 



140. Report of I'rogross of the Division of Hydrography lor the Calendar Year 1895, by Frederick 

 Hayiics Newell, lIydrograi)her in Charge. ISDtJ. 8'. 356 ]>p. Price 'J5 cents. 



141. The Koceuo Depo.-iits of the Middle Atlantic Slope in Delaware, Maryland, and Virginia, by Will- 

 iam Bullock Clark. 1896. 8^. 167 pp. 40 pi. Price 15 cents. 



142. A Brief Contribution to the Geology and Paleontology of Northwestern Louisiana, by T. Way- 

 land Vaughan. 1896. 8°. 65 pp. 4 pi. Price 10 cents. 



143. A Bibliography of Clays and the Ceramic Arts, by John C. Branner. 1896. 8'^. 114 pp. Price 

 15 cents. 



144. The Moraines of the Missouri Coteau and their Attendant Deposits, by James Kdward Todd. 

 1896. 8\ 71 pp. 21 pi. Price 10 cents. 



145. The Potomac Formation in Virginia, by W. M. Fontaine. 1896. 8^. 149 pp. 2 pi. I'rice 15 cents. 



146. Bibliography and Index of North American Geology, Paleontology, Petrology, and Miner- 

 alogy for tlie Year 1895, by F. B. Weeks. 1896. 8°. 130 pp. Price 15 cents. 



147. Eartliquakes in California in 1895, by Charles D. Perrine, Assistant Astronomer in Charge of 

 Earthquake Observations at the Lick Observatory. 1896. 8°. 23 pp. Price 5 cents. 



148. Analyses of Rocks, with a Chapter on Analytical Methods, Laboratory of the United States 

 Geological Survey, 1880 to 1896, by F.W.Clarke and W.F. Hillebrand. 1897. 8^. 306 pp. Price 20 

 cents. 



WATER-SUPPLY AND IRRIGATION PAPERS. 



By act of Congress approved June 11, 1896, the following provision was made: 



'■^Provided, That hereafter the reports of the Geological Survey in relation to the gauging of 

 streams and to the methods of utilizing the water resources may be printed in octavo form, not to 

 exceed one hundred pages in length and five thousand copies in number; one thousand copies of 

 which shall be for the otticial use of the Geological Survey, one thousand five hundred copies shall be 

 delivered to the Senate, and two thousand five hundred copies shall be delivered to the House of Rep- 

 resentatives, for distribution.' 

 Under this law the following papers have been publislied: 



1. Pumping AVater for Irrigation, by Herbert M. Wilson. 1896. 8°. 57 pp. 



2. Irrigation near Phonix, Arizona, by Arthur P. Davis. 1897. 8°. 97 pp. 



3. Sewage Irrigation, by George W. Rafter. 1897. 8^. 100 pp. 



4. A Reconnoissauce in Southeastern Washington, by Israel Cook Russell. 1897. 8°. 96 pp. 



5. Irrigation Practice on the Great Plains, by Elias Branson Cowgill. 1897. 8°. 39 pp. 



6. Underground Waters of Southwest-ern Kansas, by Erasmus Haworth. 1897. 8°. 65 pp. 

 Jn preparation : 



7. Seepage Waters of Northern Utah, by Samuel Fortier. 



8. Windmills for Irrigation, by E. C. Murphy. 



9. Irrigation near Greeley, Colorado, by David Boyd. 



10. Irrigation in Mesilla Valley, New Mexico, by F. C. Barker. 



TOPOGRAPHIC MAP OF THE UNITED STATES. 



When, in 1882, the Geological Survey was directed by law to make a geologic map of the United 

 States, there was in existence no suitable topographic map to serve as a base for the geologic map. 

 The preparation of such a topographic maj) was therefore immediately begun. About one-fifth of the 

 area of the country, excluding Alaska, has now been thus mapped. The map is published in .atlas sheets, 

 each sheet representing a small quadrangular district, as explained under the following heading. The 

 separate sheets are sold at 5 cents each when fewer than 100 copies are purchased, but when they are 

 ordered in lots of 100 or more copies, whether of the same sheet or of diflerent sheets, the price is 2cents 

 each. The mapped areas are widely scattered, nearly every State being represented. ^More than 

 800 sheets have been engraved and printed; they are tabulated by States in the Survey's "List of 

 Publications," a pamphlet which may be had on application. 



GEOLOGIC ATLAS OF THE UNITED STATES. 



The Geologic Atlas of the United States is the final form of publication of the topographic and 

 geologic maps. The atlas is issued in parts, progressively as the surveys are extended, and is 

 designed ultimately to cover the entire country. 



Under the plan adopted the entire area of the country is divided into small quadrangular districta 

 (designated quadrangles), bounded by certain meridians and parallels. The unit of survey is also the 

 unit ot publication, and the maps and descriptions of eacli quadrangular district are issued as a folio 

 of the Geologic Atlas. 



Eaoh folio contains topographic, geologic, economic, and structural maps, together w«th textual 



