ADVERTISEMENT. IX 
0. Experiments with Windmills, by T. O. Perry. 1899. 8°. 97 pp. 12 pi. 
1. Wells of Northern Indiana, by Frank Leverett. 1899. 8°. 82 pp. 2 pi. 
2. Sewage Irrigation, Part II, by George W. Rafter. 1899. 8°. 100 pp. 7 pi. 
3. Water- right Problems of the Bighorn Mountains, by Elwood Mead. 1899. 8°. 62 pp. 7 pi. 
:4. Water Resources of the State of New York, Part I, by G. W. Rafter. 1899. 8°. 99 pp. 13 pi. 
:5. Water Resources of the State of New York, Part II, by G. W. Rafter. 1899. 8°. 101-200 pp. 12 pi. 
!0. Wells of Southern Indiana (Continuation of No. 21), by Frank Leverett. 1899. 8°. 04 pp. 
!7. Operations at River Stations for 1898, Part I. 1899. 8°. 100 pp. 
58. Operations at River Stations for 1898, Part II. 1899. 8°. 101-200 pp. 
29. Wells and Windmills in Nebraska, by Erwin H. Barbour. 1899. 8°. 85 pp. 27 pi. 
50. Water Resources of the Lower Peninsula of Michigan, by Alfred C. Lane. 1899. 8°. 97 pp. 7 pi. 
51. Lower Michigan Mineral Waters, by Alfred C. Lane. 1899. 8°. 97 pp. 4 pi. 
52. Water Resources of Puerto Rico, by Herbert M. Wilson. 1899. 8°. 48 pp. 17 pi. 
53. Storage of Water on Gila River, Arizona, by Joseph B. Lippincott. 1900. 8°. 98 pp. 3:5 pi. 
'34. Geology and Water Resources of SE. South Dakota, by J. E. Todd. 1900. 8°. 34 pp. 19 pi. 
35. Operations at River Stations, 1899, Part I. 1900. 8°. 100 pp. 
30. Operations at River Stations, 1899, Part II. 1900. 8°. 101-198 pp. 
37. Operations at River Stations, 1899, Part III. 1900. 8°. 199-298 pp. 
38. Operations at River Stations, 1899, Part IV. 1900. 8°. 299-396 pp. 
39. Operations at River Stations, 1899, Part V. 1900. 8°. 397-471 pp. 
40. The Austin Dam, by Thomas U. Taylor. 1900. 8°. 51pp. 16 pi. 
41. The Windmill ; Its Efficiency and Economic Use, Pt. I, by E. C. Murphy. 1901. 8°. 72pp. 14 pi. 
42 The Windmill; Pt. II (Continuation of No. 41). 1901. 8°. 73-147 pp. 15-10 pi. 
43. Conveyance of Water, by Samuel Fortier. 1901. 8°. 80 pp. 15 pi. 
44. Profiles of Rivers, by Henry Gannett, 1901. 8°. 100 pp. 11 pi. 
t press: 
45. Water Storage on Cache Creek, California, by A. E. Chandler. 
40. Physical Characteristics of Kern River, California, by F. 14. Olmsted, and Reconnaissance of 
aba River, California, by M. Manson. 
47. Operations at River Stations, 1900, Part I. 
48. Operations at River Stations, 1900, Part II. 
49. ( (perations at River Stations, 1900, Part III. 
50. Operations at River Stations, 1900, Part IV. 
TOPOGRAPHIC MAP OF THE UNITED STATES. 
1 When, in 1882, the Geological Survey was directed by law to make a geologic map of the United 
lutes, there was in existence no suitable topographic map to serve as a base for the geologic map. 
Ifhe preparation of such a topographic map was therefore immediately begun. About one-fifth of 
he area of the country, excluding Alaska, has now been thus mapped. The map is published in 
.tlas sheets, each sheet representing a small quadrangular district, as explained under the next head- 
ng. The separate sheets are sold at 5 cents each when fewer than 100 copies are purchased, but 
vhen they are ordered in lots of 100 or more copies, whether of the same sheet or of different sheets, 
he price is 2 cents each. The mapped areas are widely scattered, nearly every State being repre- 
sented. About 1,100 sheets have been engraved and printed; descriptive circulars concerning them 
nay be had on application. 
The map sheets represent a great variety of topographic features, and with the aid of descriptive 
;ext they can be used to illustrate topographic forms. This has led to the projection of an educa- 
tional series of topographic folios, for use wherever geography is taught in high schools, academies, 
ind colleges. Of this series the first three folios have been issued, viz: 
1. Physiographic types, by Henry Gannett. 1898. Folio. Four pages of descriptive text and the fol- 
lowing topographic sheets: Fargo (N. Dak. -Minn.), a region in youth; Charleston (W.Va.), a region in 
maturity; Caldwell (Kans.), a region in old age; Palmyra (Va.), a rejuvenated region; Mount Shasta 
(Cal.), a young volcanic mountain; Eagle (Wis.), moraines; Sun Prairie (Wis.), drumlins; Donald- 
^onville (La.), river flood plains: Boothbay (Me.), a fiord coast; Atlantic City (N. J.), a barrier-beach 
oast. Price 25 cents. 
2. Physiographic types, by Henry Gannett. 1900. Folio. Eleven pages of descriptive text and the 
following topographic sheets: Norfolk ( Va.-N. C.) , a coast swamp; Marshall (Mo. ) , a graded river; Lex- 
ington (Nebr.), an overloaded stream; Harrisburg (Pa.), Appalachian ridges; Poteau Mountain (Ark.- 
[nd.T.), Ozark ridges; Marshall (Ark.), Ozark Plateau; West Denver (Colo.), hogbacks; Mount Taylor 
(N.Mex.), volcanic peaks, plateaus, and necks; Cucamonga (Cal.), alluvial cones; Crater Lake special 
(Oreg.) , a crater. Price 25 cents. 
3. Physical geography of the Texas region, by Robert T. Hill. 1900. Folio. Twelve pages of text 
(including 11 cuts); 5 sheets of special half-tone illustrations; 5 topographic sheets, one showing types 
3f mountains, three showing types of plains and scarps, and one showing types of rivers and canyons; 
ind a new map of Texas and parts of adjoining territories. Price 50 cents. 
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, or folios, 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 rectangular districts 
(designated quadrangles) , bounded by certain meridians and parallels. The unit of survey is also the 
