ADVERTISEMENT. IX 



TOPOGRAPHIC MAP OF THE UNITED STATES. 



Wheu, in lb82, the Geological Survey was directed by law to make a geologii/ map of the United 

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

 The preparation of sucli a topographic map was therefore immediately begun. Abono one-liltli of the 

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

 sheets, each sheet representing a small quadrangular distrii-r, as explained under the next head- 

 ing. 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 cojiies, whether of the same sheet or of different sheets, the 

 price is 2 cents each. I'hr niaiiped areas are widely scattered, nearly every State being represented. 

 About 900 sheets have lieen engraved and printed; they are tabulated by States in the Survey's 

 "List of Publicaticms," a paiii|ililct which may be had on application. 



The map sheets represent a great variety of topographic features, and with the aid of descriptive 

 text they can be used to illustrate topographic forms. This has led to the projection of an educational 

 series of topographic folios, for use whei'ever geography is taught in liigh schools, academies, and 

 colleges. Of this series the first folio has been issued, viz: 



1. Physiographic types, by Henry Gannett, 1898, folio, consisting of the following sheets and 4 

 pages of descriptive text: Fargo (N\ Dak. -Minn.), a region in youth ; Charleston ( \V. Va. ),a region in 

 maturity; Caldwell (Kans.), aregiou in old age; Palmyra (Va.), a rejuvenated region; Mount Shasta, 

 (Cal.), a young volcanic mountain; Eagle (Wis ), moraines; Suu Prairie (Wis.), drnmlius; Donaldson- 

 ville (La.), river flood plains; Boothbay (Xle.), aiiordcoasfc; Atlantic City (N. J.), a barrier-beach coast. 



2. Physiographic types, by Henry Gannett, 1900, folio, consisting of the following sheets and 11 

 pages of descriptive text: Norfolk (Va.-N. C), a coast swamp; Marshall (Mo.), a graded river; 

 Lexington (Nebr.), an overloaded stream; Harrisburg (Pa.), Appalachian ridges; Poteau Mountain 

 (Ark.-Ind. T.), Ozark ridges; Marshall (Ark.), Ozark Plateau; West Denver (Colo.), hogbacks; 

 Mount Taylor (N. Mex.), volcanic peaks, plateaus, and necks; Cucamonga (Cal.), alluviat cones; 

 Crater Lake special (Oreg.), a crater. 



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 rectangular districts 

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

 unit of publication, and the maps and descriptions of each rectangular district are issued as a folio of 

 the Geologic Atlas. 



Each folio contains topographic, geologic, economic, and structural maps, together with textual 

 descriptions and explanations, and is designated by the name of a principal town or of a prominent 

 natural feature within the di.strict. 



Two forms of issue have been adopted, a "library edition" and a "field edition.'' In both the 

 sheets are bound between heavy paper covers, but the library copies are permanently bound, while 

 the sheets and covers of the field copies are only temporarily wire<l together. 



Under the law a copy of each folio is sent to certain public libraries and educational institu- 

 tions. The remainder are sold at '2v> cents each, except such as contain an unusual amount of matter, 

 which are priced accordingly. Prepayment is obligatory. The folios ready for distribution are listed 

 below. 



^'^^me of sheet. 



Livingston . 



Hinggold . . . 



Placerville.. 

 Kingston . .. 



Pikes Peak (out of .stock) .. 

 Sewanec 



Antliracite-Crested Butte . 



Har])erH Ferry 



Jackson 



Estillvillu 



13 Fruaericksbu: 



14 I Staunton 



15 Lassen Peak. 



16 Knoxvillo.... 



Montana. 



fGeorgta.. 



\Teiinessec 

 California 

 TennessM 

 California 



Colorado... 

 Tennessee . 

 Colorado... 

 (Virginia... 



C.-iIilo 

 <Kenl i: 



iTcniicss,-, 



'\Nortli Cai 



Marysvillc I California 



Liiiiitiug ineridiaiu' 



Limiting parallels 



llOO-Ul" 



85°-S5° 30' 



120° 30'-121o 



84° SO'-SS" 



121°-121=' 30' 



85°-85° 30' 



1050-105° 30' 



85° 30'-86° 



106° 45'-l(l7° 15' 



77° 30'-7S° 

 120° 30' -121° 



770.770 30' 



79°-7no 30' 



121°-122° 



83° 30'-84° 



121° 30'-122° 



450_i6o 

 34° 30'-35° 

 38° 30'-38° 

 35° 30'-36o 

 38° 30'-39° 

 35°-35° 30' 

 38° 30'-39° 

 350-35° 30' 

 38° 45'-39° 



39°-39° 30' 

 380-38° 30' 

 36° 3U'-37o 



380-38° 30' 



380-38° 30' 



40O-41O 



350 30'-36° 



390-390 30' 



Price, 



