C O NTENTS The Geysers Other Hot-Water Ph e nomena Yellowstone La ke Gra nd Ca nyon of the Yellowstone Dunr aven Pass a nd Tower Fal ls Fossil For ests Sylva n Pa ss a nd Red Canyon of Shoshone Red Lodge Cooke Road . Yellowstone Tr a ils Gr ea t Wildlife Refu ge Trees Fi shing The Pa rk Se a son Admini str ation Na tur ali st Ser vic e Fr ee Publi c Ca mpgr ou nds Ra ilr oad Informa tion All -Exp ens e Tours Bus Information Airpla ne Informa tion Highwa ys to Yell owston P a rk Milepost System Mi scella neous Servi ces Accommodation s Gr a nd Teton Na t Pu bli cation s Refer ences urfa ce em er a t r es of Hot S r n s Ge sers Fumerol es S T p u p i g , y , Pr omine nt Geysers a nd Springs Rules a nd Regul ations Events of Histor ica l Importa nce na Pa rk 1n B f Natio l s r i e . U N I T E D S T A T E S D E P A R T M EN T O F E I E R I R a r o d L . I ck es S ecre tar T H N T O H l , y N T O N L P A R K S E R V C E Ar n o B . C a m m er er Di r ect o r A I A I . U N I T E D S T A T E S G O V E R N M E N T P R I N T I N G O F F I C E 1 9 3 8 s e r an r Th r posse sed by motions of wonde d myste y . e visito is power fully ’ r e e a e e e r es a re e r r r a imp ss d by s ns of n a n s to n tu s s c et labo ator ies . P actic lly t h e entire region is volcanic . Not only the su rrounding mountains but t h e rea er r are e er e e e g t int io plain mad of mat ial onc j cted , as ash and lava , ’ f r h e from depths a below t e su rface . Positive vid ence of Yellowston e s r re all t he a a s s ff volcanic o igin is appa nt to in bl ck gl s of Ob idian Cli , the whor led and contor ted breccias along t he r oad near t he top of Mount a r t he r a re e e a t he r W shbu n , and b illi ntly colo d d compos d lav walls of G and F or e t he e ere e Canyon . a long tim chi f public int st in Y llowstone centered ar ound its spouting geyser s and simil ar uncanny wonders of a dying a r r e e s r volcanic r egion . Now th t good oads and t ails hav mad thi g eat er e e s e it s ea r e r - fill ed e and rea wild n ss acc s ibl , b utiful fo sts , t out lak s st ms , and it s wild - animal p opulation attr act as many visitors as t he volcanic wond er s . THE GEYSERS Ther e are about geyser s and hot springs in t he p ark . Most of them are e t he six r e er t he rr er locat d in p incipal g ys basins , No is , Low , Midway , er e r a e e s t he e and Upp , H a t L k , and Shoshon Basin , all lying in w st south h he e er ex ar e r r a er centr al par ts of t e park . T g ys s hibit a l g va iety of cha ct l d is and er e e and a . e e O ction Som , lik Faithful , Da y , R iv sid , spout at quit rs ar e regular inter vals ; others are irregular . Some bu t upw d with imm nse in power ; other s shoot streams at angles or bubble and foam action . Geysers occu r only at places where t he high temperatures of t he d epths he e an a of t he ear th appr oach close to t h e surfac e . Much of t h at and ppre r ciabl e amount of gas and steam are added from consid e able depths . er r r a e r r r t he r s or a er Wat f om the su f c t ickling th ough c acks in ock , w t ’ from subterr an ean seeps collecting in t he geyser s plumbing down in the re e s e e e e e e ea e r s e gion of int n e h at , b com s its lf int ns ly h t d and fo ms t am, Wt h expands and forces upward t he cool er w ater that lies above it . I t is then that t he water at t h e su rface of t he geyser begins to bubbl e and es s a r s a t h e e er is a . giv off cloud of v po , a ign th t g ys bout to play The tube or pl umbing of t he geyser must b e cr ooked or constricted suffi i e ea e cient l y to prevent easy cir culation of t h e water . With cont nu d h t b ing ’ a e r e t he er t he t he e ser s e e a s ppli d f om b low , wat in bottom of g y tub xp nd so that t he l ess - heated column above can no longer weigh it down ; then water bubbl es over and r elieves t he pr essure of t h e super heated water e s e s es e s t he e r e r b low , which udd nly fla h into st am, pu hing nti mass upwa d h er an t h a r r e a ee t he air in an er uption . Then t e wat d e v po is m ny f t into i The and continu e to play until p r ac t ically all of t he geyser s cleared . a er e and a a t he r r s off or er a er w t , cool d f lling b ck to g ound , un , with oth w t , 2 Y E L L O W S T O NE N A T I O N A L PA R K W Y O M I N G ’ r er re t he e r e r e er or seeps into t he g ound to gath as befo in g yse s d pth , in a g at e t he e t h e e er er . less time becomes heat d to xplosion point , and g ys upts again r e e er f r Natu ally, ach g ys has a dif e ent plumbing , and it follows that it er a t h e er a t h e has a diff erent behavior . I n the geys b sins mat i l making up r t he er s r e walls of t he c acks and tubes of geys s is of silica , and t ong nough to h e e he a . es r er s withstand t e xplosiv action of t ste m A l s st ong mat ial , uch r e e e e as trave tin , will not withstand this xplosiv action and h nce will not r produce geyse s . OTHER HOT -WATER PHENOMENA Near ly t he entire Yellowstone r egion is remarkable for its hot - water The r r e er are. e ree s phenomena . mo e p ominent g ys s confin d to th ba ins r e r t he e r r t he r er lying n ea ach othe in west c nt al pa t of pa k , but oth hot water manifestations occur at mor e widely separ ated points . Marvel sl re r s er r e e ou y colo d hot sp ing , mud volcanoes , and oth st ang ph nomena are frequent . In certain areas hot water has brought to t he su rface qu antities of white r l e erra e e r e a mine a d posits which build high t c s of b autifully inc ust d b sins , h often engulfing trees of consid er able size . T e hot water flows over the edges of these fr etted basins . Micr oscopic plants called algae gr ow on t he edges and sid es of these ra e red r and basins , deco ting them with hu s of , pink , tan , b own , bluish r r .