BULLETIN 611 
SHEET No. 16 
N20" 
MONTANA 
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EOLOGIC AND TOPOGRAPHIC MAP < RY 4), J $ 
G O. OG D O OG Soe y) pi Sy bet, i: Sp 7) y = Rep N 
OF THE ‘ae got Z Mid ages, y t 7 Sa o 
FE ie A pr win SAK KS ® 
NORTHERN PACIFIC ROUTE IIT OO ios eee BOON ; 
} TO Po ona FS OSS 
ZUNS CS a vi . i 
e ; S / 4 KE, Ae ye SAS ey / 
From St. Paul, Minnesota, to Seattle, Washington > ML LEPC ae fe), a 
A og AC arfisop 
Base compiled from United States Geological Survey Atlas 5)\ eZ 
Sheets, from railroad alignments and profiles supplied by A Stree dépeaite tolltiviaw) OS 
the Northern Pacific Railway Company and from additional B Gravel, sand, and voleanic ash ; 
information collected with the assistance of this company dake beds) 000 Late Tertiary | 
Dark shale, (Colorado) 1,900 Upper Cretaceous 
UNITED STATES GEOLOGICAL SURVEY ctad teweieny | 
E 4 (Kootenai formation) 900 Lower Cretaceous 
} be, iaee 7? | 
GEORGE OTIS SMITH, DIRECTOR (Ellis formation) _ 400 Jurassic Maeria 
: : r : A Sandstone and impure limeston -; 
David White, Chief Geologist R. B. Marshall, Chief Geographer WE} <tica leant formation) "| aos Gebbeaiferwe : | 
1915 Massive blue limestone (Madison) “ i 2) 
nN < Shale and shaly limestone Oo sf 
¢ g ii (Threeforks shale) 1,000 Devonian & of 
Each quadrangle sh the map with a name in parenthesis in the ; $ § Dark limestone (Jefferson ) 4 Scale 500,000 | Av 
lower left corner is mapped in detail on the U. S. G. S. Topographic 45|* s e (Gallatin) a \ Approximately 8 miles to 1 inch \ 45, 
Sheet of that name. a Shale, limestone, and sandstone 1,300 Cambrian 1 % 20Miles 30 
\ (Flathead formation) we net rt nn ate srt cnn rete nna 
L ale, limestone, sandstone, and iometers 
conglomerate (Belt series) 8,000 Algonkian 7 oot To oe OE 30K 
M_ Gneiss and schist Archean Costéae terial 200 tout 
R_ Lava flows, dacite, and rhyolite eS . — 
S Granite, intrusive The dis from St. Paul, Minnesota h 10 
T Lava flows‘and intrusive masses, andesite The crossties on the railroads are spaced | mile apart 
12°30" n2° 11°30" 
