= fe Me ot ba Boa Pei taes re = : ie ork aE Regs eent mE L Sy : us : ey apex WRN SSS, kx rate eens! sacansee ana part as ros S33 St ee = i, Cor eae Tak weit 0014 2498 -<— ~ — Se woes ee) es eT 65 Section’ I. Springs on Yellowstone River Draingage............-.----.---- 71 Cuap. I, Mammoth or White Mountain Hot Springs of Gardiner’s River. . 71 Table of Mammoth Hot Springs 73 DWESCuIpITOMEGBNDEINON oon cence ob ccpaciacles nse ain aki se secsee 74 II. Springs of Yellowstone River below the Grand Falls, including ee Pipe RMON ate toe atl atte micine aals ptieisiete, ain aod owe eon en 3 84 SBNCHOM WalleyaSOUIN OS << sce. 2 ceca mn/eediselecatidtine siccnee 2 84 RON OMO RES kel SPUN OS sa ae eo se ase aimiaiei sis iai= © aeisinie oa ninjesiore 84 Springs on East Fork of Yellowstone. ....-....-.-..-------- 85 Moun pa ViaS ODUM GROUPS ie cece secisicicsc viceaceccsisccsecs sacs 86 VI TABLE OF CONTENTS. Page. SrcTION I.—Continued. : Cuap. I1.—Continued. Springs of the Grand Cafion ........-----------------+----- 88 \Waiyencle. CROWD caso cous G6nd06 Hondo0 dooe dedisos Sa00 cacn sana 89 Orange @reel Springspesssse5.0- bee 2 eee anes s 89 Recapitulgitomee cece sncle sae oe ae ae lela) lone lala ietnl 90 III. Hayden’s Valley Springs .----...---. ------ ---- .----+ ---- ------ 90 Orem 18M ooo 455555 coocoa sabe bonD DOGO BEGG UEOSSS Beaded ccs 91 Table of Crater Hills Springs --..-------.------------------ 93 Mud) Volcanoes or Mud (Springs 22. 4220) - ce sae epee 94 Table of Springs at Mud Volcanoes ...--.------------ ------ Anos Waolet Greek Spring ge eees sae soc) see eee eee eee 106 Warm Spring Creek or Prairie Group ...---.----------- ---- 108 Boiling Springs on Warm Spring Creek ...--..----.-------- 109 IBAA ROINE CHOU sos 25 asscco od aees coaso9 ConSbo oaScue bodese 111 Recapitulation Hayden’s Valley Springs ..----------------- 112 IV. Springs of Yellowstone Lake ........-...---------------------- 112 yuh ovonope JENS os S465 eeks Sho6 Geckos sb opuens odbeee ceao aces 113 PurbidiwakerGrowp eee yee ee ese eters elas eee eys ela altos 114 Hise oN NORNG SUAS ook ocsk cseses caekeo Goseds coeose sacs anes 115 Wena Bey CnROU) 55554 e555 coches coseooeoone boon enosde Sess 116 ake Butte Springs see ssee eee eee eee re ee eee eerie reise 117 IBIAS MONS JBORIING oan cana soa ASSUMbooKeS SaeobS does boos onsSeC 117 Sprinesjatpheadioimaine) Creeks eee reee eee ele ee 117 Springs on west arm of Yellowstone Lake.......-.-....---- 118 Recapiiulationtesee see eee sees eee ee eee ete eee eceieerers 120 Wapeelicani@reelkas prinessas seme eee esses eee eee ee aac eae 120 WestiPelicant Creek Springspeee eee eeseeee eee eee eae eee 121 Relicant Creek MudiViolcano se ananee sees e eines 122 Recapitulation Pelican Creek Springs..-....-....---------- 123 SrecTIon II. Springs on Madison River Drainage..........-...------.+-.---- 124 CHAE, Ws Ent hioom Iehyere SohnNss o-oo phos coecoscasse coses cog550 Ge0nc0 coor 124 GibboniGeyseniBasineee essen erste ee eye eee cients 124 Table of springs..--.-.---- sdodicgseososess doacce becesatacssc 125 Deserip tor Meee ee RGN Oe eG, | AE hk eae 125 Monument Geysersinas -eereee cee Caaere erase ieee ence 132 Wower GrompronsGibbonsshorkeeseeee sa asae ee eee — 133 Recapitulation Gibbon River Springs. ---:------.----...-22: 13 VII. Lower Geyser Basin of Hire Hole River --.- .--..----.---.--2--- 135 HasteHorks Sulphur Sprines eee eee eee eee seein eee 136 Hirstoribast orkeGroupeees se secee seer eee eee 15 Mabletor the Hast bork Groupeecees tes see sees eee Eeee 138 Description of the East Fork Group..---..-.--.---...-------- 139 Butte Grow eee ee ee Ne ena aoe LG AN ea aoe ee 141 Camp Group eae ee ee ee aya ein (ee eT le ote ae ae 142 hablevot Camp GrompH SpE CS eee eee ae eee eee 142 Description of Camp) Group Springs) s2e5 ss seaeeeee eee eee 143 Secondor Mh ud Gro ups ees ee ere a ee 144 Tablejot “Fhud Group sess esses se eee eee ae 144 Hhirdsor-Hountaim\Groupeseseesee ees eee eee eee eee eee 147 GableoLhountain’ Groupes snes ss eae eee ee eee 148 Description of Mountain) Grompeessese eee sense eee ee eee eee 149 Mourthior Pussure:Gromp se ssecee ek eee eee ee eee eeeee 155 Table of Fissure Group... SP OE Aa 156 TABLE OF CONTENTS. Vil SEecTION II.—Continued. ee Cuap. VII.—Continued. Desexipion ol Hussire GLOMPcec ant ames els acloms = ils eu = alee 157 HitthrorawihitesWome:Groupieccsassseeseeoseee- eee ec ss one 159 ANOS GE \yyinuivey IDYorasrs (Caran) 06 eon Boal AB Amado doee nees 160 Description of White Dome Group ...-....---..--.-.-.----- 162 SISA OP INVER CiROUO)s.b5 os pecdeacoesos ace sscoe sous sane ceeS 166 MaMlevoimhunjer) GrOW peasant eree ssi piss se sea 167 DeschipmonsOr WLyer GLOUples= seeeeeiacetinces isi-s ce sie 170 GoosetbakesMud! Springsesye seeee stele ciisinloseiee ola cee oc/5 172 Seventh Group or Fairy Falls Springs.....---,--...---.---- 172 Deol OF IaAy WRMNS Ciro Dosccdo classe aeoosese cebeseonador 173 Weseriphion oO Maing HallsiGnroupeseseceee se a2204--255 =~. 174 PiMhihror Sem bin el Grom pees sectarian) oie elas clela = 175 able oR Sentinel Growpre sate seee sae eee sleeisisie ae elercise orale 176 Descriphionrot sentinel Groupysesrmasciem esa a elja ee eee ae 176 Halfway Groupior Egeria Springs -..--.--.52..- -2-.-----.. 178 Mayle Ot Lees, SMOGS Aoocs todoos seoSoe's So00 Seee50 965550 179 Descriphironvor sh Tera OpriMesesecict ee slesee eal) elle 180 Ina olou 1B AClN SOWING Shas toad saeco coe soedee bedoos5eEs 180 Recapitulation of Springs and Geysers of the Lower Geyser BRIS -adGs sean ede amon aneoos sHodaeoedo cubaacomeoUoUoTeSEHEG 186 Millie, Dipper Geyser Basin of Hire Hole River ------2----------------- | 167 Soden, Geyser COU csebbosos osobbe cess ees qaeoes code ones 188 TRVGIE (Gal@tD) Soo SHR Sebo eee Soe ones ose5 uppeneesas esos core 188 CaS@AG® (CMOUN. Soss6 soséeke se ese ates booebe S5ec sae Seeou eds 189 (GGT) CROWD cacomeee AAeesbo snob cooomseocucTcn Bae seen immed ters) IMINOGrE Exoinw Crrowh) 25s se6 chase csdoove sess socbeoseeecc 189 MeserpilonroGrOotvo) GTOmp as: ites aerate sa) cin = ora 190 Ghai CHOND aonesb sho Goda cacbb0 onndoy esaee5 coSson shes asce 194 Mahleot phe Granti Growpessas- ieee erase seiscisce caceiaee's 195 Rewind! Syominsr Crews 686 sos so5c Seocda cuss beso opee ones S656 199 Maple taesvoun du sprimes Grow peer sees soe aelete slr 199 Wikies varcamirdy Gr OU pee senees ayers stele esiciare st a telale= er 200 Table of the White Pyramid Group..--.--.---------------- 200 Description of the White Pyramid Group. .-..--....---.----- 200 @astle Groupee seo ees oe seme teat aycisicis aie sine slo sinicis ere 203 Mallet uheiCasple | Gropp ese ee ernie sliseiei15-) == 1sia = ce 204 Description ofthe Castle Group... -- -..--2-scs-cescncccae 204 Table of eruptions of Castle Geyser .-...-....--...----..-.. 207 Gimndl CmOWDs65 coeebe Ceadees eae abe on Geog nada se cEecmasaeos 209 Majole Or aoe Camel Crea) sese ke soos ode seo paeosopeeee cosohc 209 Description of the Grand Group...-----22-...----.--..--... 211 Old Moti) Coron iy SeSabassseeesoskse ss oous ao esesooss sods 219 Mevoievow (Oil Whyqamil Cio s) Sass as aoaeae canals sobsccbesooe 220 Deseription of Old Faithful Group .----..--..----. ---..--.- 220 Table of observations of 1872 on Old Faithful Geyser..----- 222 Table of Comstock’s observations .......--.---------------- 223 Table of observations on Old Faithful, 1878..---.-.--.----- 225 Table of comparison of OSM EEEOES on Old Faithful Geyser. 229 (Ui gyorere SiomabaUSy pA GoSeneesonconeecuereene RA ae a ees 229 AUER HATO SS OLOU Disa ase cl aisialeleie te |e icin inte eeielnn einle/ninnl-/== 230 Wale Gl anLOSSG LOM Pesan a) eccicie niece a cessicnie 6 -mia= eta = 230 Description of Giantess Group .... 202. 202 ceenneceeees eee 232 Viil TABLE OF CONTENTS. SECTION II.—Continued. Cuap. VIII.—Continued. Table of eruptions of Bee Hive Geyser in 1878 -..-.....---- Table showing comparison of observations on the Bee Hive (GREW Ser? do bans Gosuoabon cos uoMeod seca Oean Gece ss|5So5socan5cs 237 Three Crater GLOMpieseeee cece lass esi a= =e 2 =m eee 239 Table of the Three Crater Group .------..----- ------------ 240 Description of the Three Crater Group-.-.----------------- 24 TMT! CROWD saosco caus boau Haase aedunEs Guco cose dase cosce 244 Table of the Emerald Group. ---.-----.-------:-2--=------- » 245 Description of the Emerald Group ..-.--..------------------ 245 Throrn Syormihoee CHOW s) psstdo sad baad seba dss bose cosa He Sooo sons 247 Recapitulation of Springs and Geysers of Upper GeyserBasin. 247 IX. Third Geyser Basin of Fire Hole River .....--..--.-------.---- 248 SEcTIon III. Springs on Snake River Drainage....-..------------------- +--+ 249 CHAP XE Shoshome) Gey seryb asinine piss ores ore es ola) cie eine le ee cefenere tate 249 The Orion Groupee ce. cys eee seks dais aee a ea cee Seine eins amen able jotpthe OrionkGrompeeccesss sees es ee eae ae eer 252 Description of the Orion Group .----.--.------------------ 254 Tables of eruptions of Union Geyser-.....-.----------.----- 258 Table of temperatures of Union Geyser, taken in 1878-..... 259 (Oprira§ 1) (Coy OAM A SEPA MEU AC A CA AN SS he Oe Boos 260 oben len CrROMD 6b seo doses esedon Sosboo eons Goed coo abe Scos 260 Table of the Minute Man Group -....---.-.------------------ 267 heseittle Giamti Grow pees reee eee ae ee ieee 268 Table of the Little Giant Group --....--...---------.------ 270 Sioulljolowwoe WMG) oe os obo doe eedase boosoo cooece soeoes boOG Sasa 271 Table of Sulphur Hills Group........----.----- ------------ 272 MablevormohoresGrowpeeeeeotaeeaeeeecicioaa eee ee -eieeeae 272 Ibelae) CheOW) OSG dace Gdases Hoas Oe boud Hobous CdooddoNeueosdoSsEs 273 Tableof the Lake Group) -22222 222025 2 2- oon. ween e oe == 273 Niestern(Groupreeeceieccince aoe eee see eee ees ee seer 274 Table of the Western Group or Division...-..-----.---.---- 275 Description of the Western Group ..---.--.---------------- 278 TslandiGronpeeesseee ems secs et eee eee eee lear ere 279 MIDIS Oe Iislenoel C5rom) oc6cocsed5b besad6s cons GnocGuseas Goce 280 SOMO (CROWD sascee codads copbss badbes socc Goes so SSEs onoDee os ~ 280 Maplerok they SombMnG Loupe ceeeae eee eae eee ae ise ar 281 Description of the South Group...-....---.---..--.-------- 281 INGEN (CMOND seecns Goashs H406 cond bossa coda ds obee oseooeccss 233 Mable oLtheryNorthiGrompeetaren cs sceciecerc enlace coarse eee 283: Description of the North Group.....--.-...-----.---------- 285 Wellowy Craiier Caxonyp cos ek deen sesconasesiongons nqcosaasdeso 287 Table of the Yellow Crater Group ..-.-...---------..------ 287 Recapitulation of Springs and Geysers of Shoshone Geyser 1 SFeNcyha WM oa ea eee TN Re ep Ne cI ge ROE a So A GAS 288 Xi. Heart Wake Gey serv asim ee eee yee ech SMe os See aa mee 289 Watch Creeloi Sprig eames rete sae elie eee ae reer 290 hoy cere Caro Os secs SeS5 44S CRGs Sau ddspoodad seeodd osed bhoses 291 Table of Upper Group..---.------------++---- ------------- 292 MIssure Grompeeaseitece ce ieee a stess cialenie ceo tate eee ace 293 Table of the Fissure Group .---------------------------«--« 294 Description of the Fissure Group ......---..-----.----+---- 295 Middle Growp ike so See aera a ree is Ne SY ee aerate 296 Table of the Middle Group ---...-----. .----. ------ s20 soe 297 TABLE OF CONTENTS. Ix Page SEecTION III.—Continued. Cusp. XI.—Continued. DowerdGaomp gece sadn naree rene aera sete ae fos PL LL 297 Kalblerotpuhep ower Group eecs eres eee sees sane coe eee 297 Lenitieven (ERR STESD as Seat cic eae eicel cece icy Ment aca ayy na ela UR 298 Recapitulation of Springs and Geysers of Heart Lake Basin.. 299 XII. Hot Springs of Lewis Lake and Snake River...--.........-...- 300 Hon Sprmes ore wis Wakene coe -scsisentas sane 'saue elke. 300 Sprnesions snake: River coasts ee es 300 Grand recapitulation of Springs and Geysers of Yellowstone Wariona ler ark: Caran sass Ses emanate tei nme ce cee als eu 302 PART II. THERMAL SPRINGS AND GEYSERS J ONTIRG DS IE TN Gas sedees feo bod be Pe Sec Bee AURA ee ho OG a Bree RaB ana Ger gasee 304 CuaPTeR' JI. Thermal springs and geysers of Iceland..--..-----...-...------ 304 OS Ea eh ee VAS) UT A Rs Pe ea eg 305 veil Ora hue yiktui Maas sasha gee) a Se AE Sa soa 305 SEA Ud schlieren ee ey weak nye eC eraters skl ia 305 Table showing intervals of eruptions of Great Geyser....-. 307 Table of duration of eruptions of Great Geyser...... ..-.-- 308 Table of observations on the Great Geyser..........-.-..-- 309 Table of observations on Strokhr Geyser......---.--..----- 310 Table of hot springs and geysers of Iceland .--.-.......... 311 II. Thermal springs and geysers of New HOMaAnCaanceedseenneseees OLS STG cae FUE arp OAT Ea Nk a es SE a eS ee SS 314 Rotomahamayareahs 25 ie Voie wets ese yy WN a Pee ele 314 Wihakaarior White Tsland\essescce he ee ae 316 OnakeikoralOsared Eo fata ce come ela eek eaten Sela Gea 316 iP Alt Od aval CLARO A es tetavehoh. pppoe RN per dN ime oie See 317 Re foriaparedre nea; at Lee) eee ate Meena 222 12 ake oleae 317 Table of New Zealand springs and geysers..............--. 318 Iif. Thermal ‘springs of the United States.-.--...-....--..22...---- 320 (Eber Geysersyons@ aiiforui aces eee es pa SO ahh Ute le a 321 Steamboat springs Of Nevadaleesesens ec. Seen 321 Woleano Springs oso Mas Soe clauinnn ica Settnes oe ke ua Le 322 Mud volcanoes of Southern California -...................- 323 Gramine Creek, bovinaeiSpringsee van eee eis eee ss. isle 323 Table of thermal springs of the United States -........._-- 324 IV. Thermal springs of Mexico, Central America, West Indies, and PO Uta AMIN CTE C AAs 2 rN e FN Nate RURAL DANN ou Mle rar 327 Mexieorann Central America tatss) see eee cee wees 327 RWCRUBUTICLE Si eerie Mem yaar, MA a ict re 28 SOMMMELOTOMO UNM CLA eee nate cee ie See en Sees 328 Bomineeaice ta Mommies oo 55h. fee Mel eos. sede Se 328 DhesPenteiSoutriereot Dominica 22. .226 8 e2 2522-222. 329 FS (Outta), Je Tony SEEN ie a aE ey fa Ae 329 Bathsrom Chiba. iC hile tees alececice tone eee ocak ces =2 330 Table of thermal springs of Mexico, &¢ -....--..---.-- 330 Y. Thermal springs of Europe, the ans Africa, and the Tecan (OVC EH IA A GMS COE Oe ESA ECT EAE Sith Beh Sa 332 Table of thermal springs of Enrope-...---. Pre seat shee s celr e 334 Thermal springs of the Azores, Africa, &c .-.....-....---- a) 880 Pies Caldomos Outhe AZOVEB Gees obese nase beda co ticcdescieae 337 x TABLE OF CONTENTS. Page. CHAPTER V.—Continued. African thermal springs ......---.0--+- -0---+ e2-- e----- 338 Springs of Hammam Meskhoutine-..--.-..---------------- 338 Table of thermal springs of the Azores, &c --..---.----...- 300 VI. Thermal springs of Asia Minor and Asia .....----------- ------- 339 Agila MUTGOR ocooao5d baoe coeboe CUbeES Goueouoeboes BeosoD cana 339 Somncyeysy Ort Jabigmy NOS 538 3 Sao 8 Gobo peoedd ieee cegecs csdaa5 340 INSTA) Cobk Goabed c6ba CdaadelbcouRebeee GaeEso eras odds Hosonds6¢ 340 The hot springs and geysers of Thibet --...-.-------.------ 341 Table of thermal springs of Asia Minor and Asia .....-.---. 342 VII. Thermal springs of Japan, Formosa, Malaysia, Australasia, and TROIS Soco65 be4 SKS bodond HonoEd sosGud bene ooaaK™ cacacs S 345 Japanese) thermal springs) -s--\-- cc. --2= 22 see ee sear 345 INOOTMOSRccooao ceno Codeb0 soc so oorEdE one deo saab ocodK Soe sac 347 Malaysia or the Eastern Archipelago .-...--..----.-------- 347 Mane JPowbyoyobne USNews aoe ssacossecsecsa so56 cooese cose 348 Wane) MOURCCES oocde6 sodces Hogeko becb bane 6cidode S500 HoSaoC 348 OMNES sco db66 Ssba bos e4\bkSs cose bees S55beoas'bsoes6 Goce 348 CS ies ae ea UR IO ents Aye e siote ope denise cin 21 oe eo EE aWavey ellen, Oe Diveraar OSG nad Sma ks k co ososee sodd cone 349 Springs at Bongas Valley ......--------------------. 300 EDOM OVO RTOS Sane SE ee oe gdoeeae oeaoouTads 6 300 fe) WEITERE) Goad Gasalicoas Skasco ass5a6 don0 onScde cosscoudEead > 300 PNTUUSL GEN EAST He el SS A aN Ce CaS BB eo noeauaae 351 Poly mesia a. See ayes eave ace mou fayette para enlnte ep erate ole eel al olistate (ene 351 Table of thermal springs of Japan, &¢ .....-..-...-------- dol PARTIII. THERMO-HYDROLOGY. IS TROWIOT CMO 645066 asoo50 645006 C650 Bon8 Senos So ooSsoo no Stoo Odno cObeSe 060 cose 300 SECHRION | Generaliteaturesepeece seco eo ee een a pee casieeie eee ce ene ieee 306 Cuap. I. Definition of thermal spring—Source of water—Outflow—Life in hot springs, and distribution..-.-...--- PIR At ene 306 Dennition of thermallsprimgs see) 2 2 2 eee one cee 22s ea 306 SOULCE OL waters pri Ose see eee eee ays ilo ele eee 306 OutHow ofsprimgss sis eee eee sae clea a ee 357 Ibphes) shal LOMO (SNS Soo Goo Good dob bode Guoo Resa Haobeaanes ce JF 358 ; The distribution of thermal springs ....---.-...-.---.---.- 360 ik Geologicaliteatunesiesseaeecsee eee oes eee Aerepbeeoouens 361 Geological ost tion eye es ose ve ee sin ecete ex ne eae aa ee 361 he ettects\otiearbhiqualkesseascesas sees eee eee eee 363 iis Classitvcationvand iiherapeulticseeeesse esse eee eee eee eee 364 Classification) so Naas ae Soins Spa ag oo 8 OSS Som ape eas 364 Pherapeubleseaasesmerese eee meals slniclnisie is nisralapeye terete 307 VE) Companrisoniotimeyserire cons) saereesec cise eee ae ee eee 368 SECTION UI. Physical and thermal conditions222-22 4222222252. soo oe. eee eee 372 CuHap. VY. Forms of basins, ornamentation, and color of the water......-.-. 372 Forms of basins and ornamentation .-_-..-.---..--.-------- 372 Onithe, color {ofiwrarter sae asaya ola ee 373 Wis Demipera ture ese, ee eee ae ee Cd Sa 380 HSourceotsheatheseeaeeee seer eee SSIES RUAN Olas yc epee 380 Changes of tempenaturepsee sess see ae sae eee Cee eee eee 384 Comparison of surface and deep temperatures........---.- 386 TABLE OF CONTENTS. XI Page Section II.—Continued Cuap. VII. Chemistry of thermal waters, by A. C. PEALE and HENRY ITU VUANIN ae Sage BS OSE See Ceres Bote Sees Hele Sieh ake sas 387 ATyalySEStOh Walersts sacccocs see ct eceesse coe veseck stccee 387 @alcareousor calere wabers)so.-2 eens s to: Soe ees oo ee 388 ibiCeOusStwialerseomee se ata e see eect oa isiecusasce css 390 Hire-HOlel Geyser basianes cece asain 390 Gubbony Geyser! basimisse entesse on tein eer aac eee 391 Table comparing waters from different geyser regions ..... 393 _ Table showing comparison of silica, &c.,in thermal waters. 394 Solid constituents of thermal waters.-.-..-.---....-....-- 395 Source of silica in thermal waters.-.....--..-.--..... 395 Soureeob phercarbonalesee sesame aeeereaee eee 397 Sulphur and sulphuretted hydrogen.--..--.4----.-.. 397 ANU AA iat isa tee aN es eetelaserete weeps Soe os Gta 397 SHORONPL MSs ormationsrand depositszss acevo sae ee aceccicess =~ uy ( RS ‘ \ \ =< 1 CNS O~Fy SN BASALT: ° MT/EVARTS HOLMES. ] _ DISPLACEMENT, YELLOWSTONE VALLEY. 7 voleanic conglomerates that form the bulk of Sepulchre Mountain seem to form a continuous and unbroken series. From the mouth of Cache Creek to the mouth of Gardiner’s River the Yellowstone River remains in the synclinal told which appears at e in Section A, and at bin Section B. The line of the fault probably runs nearly parallel to this fold, but is from one to two miles to the north. Between the river and the fault-line is a broad, irregular bench which has a general elevation of 200 or 309 feet above the river. Outcrops of shales and sandstones, the former gray and the latter yellow and white, occur all along the steep face of this bench. They have a strike nearly parallel with the river. In most cases they dip at steep angles, but in places seem to fold over the front of the bluffs and lie in a more or less horizontal pesition on the upper surface of the bench. A notable feature of this bench is the very plentiful occurrence of basaltic rocks. All along the bluff face there are dark irregular seams of basalt; they do not lie conformably with the sedimentary strata but cut across at various angles as if intruded into their present posi- tion subsequently to the folding vf the strata. On the upper surface of the bench, and exiending back to the base of the mountain slopes, are very numerous sheets and masses of basalt, which break off in benches, the fallen portions forming dark slides of débris. The smooth slopes of the mountains that rise behind the low bench have an obscure benched appearance that is doubtless partly owing te the existence of soil-covered lava-flows, but which must be chietly the result of ancient river action. What can be seen of the Section in the middle portion of the bench is given in Section C. At the mouth of Bear Gulch we have some interesting features. The lineof the fault here crosses the river obliquely from the north to the south side. Portions of the Cretaceous strata have been caught in the irregu- lar wall of the ascending schists and quartzites of the north side of the fault, and appear in positions such as are indicated at d in Section D. Large masses of yellowish sandstone strata just west of Bear Creek now stand on edge or incline at steep angles. The Cretaceous shales and shaly sandstones which form the river banks for some distance below the mouth of Bear Creek dip at various angies and are very much dis- located. ‘The strata near Bear Gulch are in places quite brilliant in color, probably from mineral stains which owe their presence to the action of ancient hot springs. At the junction of Bear Creek with the Yellowstone, on the right bank of the former, there is at present a small group of springs, the deposits of which extend down to the river bank. On the south bank of the Yellowstone, opposite the mouth of Bear Creek, there stands a small butte which is capped by a heavy mass of ancient calca:eous hot spring deposit. The deposit is some 20 or 25 feet thick, is yellowish in color, and so compact that it has, at a little dis- tance, the appearance of compact limestone. The base of the butte is composed of the vertical shales, and these are underlaid by the meta- morphic quartzites that haverisen beneath them. The antiquity of the siliceous deposit of the capping is made evident by the advanced state of erosion of the underlying strata, as well as by the fact that the sum- mit of the butte, now at an elevation of some 200 feet above the river, is covered with huge rounded granite bowlders, which were doubtless transported from a “point far up the cation while the bed of the river was still above the level of the present summit of the butte. (See Section I.) In the bed of the river beneath the butte and forming the walls of the third caiiou which extends from this point to Junction Valley, are 8 REPORT UNITED STATES GEOLOGICAL SURVEY. the hard metamorphic quartzites and quartzitic schists, the affinities of which puzzle me very much. It is not at all improbable that they con- sist chiefly of altered and distorted Paleozoic or even Mesozoic strata. With the exception, however, of a few fragments, which are shown at 7% in Section K, there is but slight resemblance to these formations. The river for a short distance above Bear Creek passes over a very rough bed of dark-gray quartzites, and the water has worn deep holes in the bottom and sides. Near by, on the south side, a rugged crag rises from the rivet bank, on which an eagle has built its nest. From this point, as far up as the mouth of Hell Roaring Creek, the river flows over a bed of granitic rocks. The blutfs on the north side of the river, both east and west of Bear Creek, are capped by horizontal beds of basalt, as shown in Section D. These are probably remnants of sheets which once covered a great part of the valley below. Below the mouth of Gardiner River, on the south side of the Yellow- stone, we have a series of vertical strata that run almost parallel with the river. Such of these strata as appear above the deposits of drift material are sandstones, which have a greenish color, and resemble very much some of the Tertiary strata of Amethyst Mountain. At one locality near the road, and perhaps a mile below Gurdiner’s River, I ob- tained a few impressions of leaves which are considered by Professor Lesquereux to indicate the Cretaceous age of the beds. This same series of strata crosses the course of Gardiner River near its mouth and continues along the south side of the fault-line to the valley of Black-tail-deer Creek. The outcrop in a little butte that lies just above the confluence of Gardiner River and the Yellowstone, aud at a number of points tarther up has always a vertical position. In tracing the displacement eastward from the mouth of Bear Creek we find that a high ridge of metamorphic rock interposes itself between the line of the fault and the cafon. This ridge is broken in two or three places by transverse drainage, but may be followed as far as the mouth of Black-tail-deer Creek. It is composed principally of schists that have a decided quartzitic character, and evidently belong to the same series as the similar formations no‘iced at the month of Bear Creek. The general appearance of the ridge indicates a stratified character par- allel with the fold. The schists north of the river are, however, discon- nected with the fold, as they have a strike to the north with a steep easterly dip. Along the depression west of the rid ge of quartzitic schists just men- tioned the Cretaceous and possibly part of the Post-Cretaceous strata are folded back upon the strata that form the north slope of Mount Evarts. At afew points rising against the schistose ridge there are outcrops of gnarled limestones that are probably Paleozoic. They have doubtless been dragged up in the fault. Farther on to the east we come upon a group of high, reddish hills which overlook the cafion to the north and Black-tail-deer Creek to the east. In the southern faces of these hills the characteristic Meso- zoic Red Beds appear, and the Jurassic and Lower Cretaceous forma- tions outcrop along the south base. All of these formations are vertical, or nearly so. The strike makes an abrupt turn to the north around the southeastern base of the hills, but soon returns to a southeasterly diree- tion. Forming the summits of some of the higher points of the hills are - outcrops of metamorphosed and distorted sirata that have evidently been involved in the fault. Between these hills and the highest part of wean Evarts there are = PSOne An yh Secrion D. e Slope of Mount Evarts. Jf Quartzites and schists. b Vertical sandstone. e Sheets columnar. basalt. a Yellowstone River. d Dragged fragments of Cretaceous strata. I Very \ ay W-RNAS Vv SECTION E, ») Hot Spring limestone. c¢ Granite bowlders. d Vertical sandstones. g Bear Guich. h Basalts. i Quartzites. a Yellowstone River. f Hot springs and deposits. eSlope of Mount Evarts. ae £ > oR Zi ~ See 5 ; LA ae bf. SALT WY Uj Rika Zo ses.. “Wi Vy = y ies QB. fee Oe at lI {( : Z ahr Ac & 2 ey a ‘Tn — Ce Aid . wee ie Set \! 2 A ie. 2 aa eae io SECTION F. d Red beds. eCrumpled quartzites. h Gardiner’s River. a Yellowstone River. b Miea-sehist, &e. g Mount Eyarts e Lower Cretaceous strata. f Middle and Upper Cretaceous. Plate IV.—Geology of Yellowstone Valley. HOLMES. | GEOLOGY OF MOUNT EVARTS. 9 a series of ridges, or hog-backs, which include a duplicate set of strata produced by the folding back on themselves of the Upper Cretaceous and Post-Cretaceous (?) rocks. (See Section F.) ‘These strata are so ob- scured by soil and vegetation that one can neither determine their exact character nor say just where the axis of the fold runs. As the distance is upward of three miles, and the dip mostly quite steep, the series of strata must be very large. This apparent thickness of strata makes it seem probable that they comprise, besides the Middle and Upper Creta- ceous, at least a part of the Post-Cretaceous or Laramie Group. On the eastern slope of Mount Evarts and in the valley of Black- tail-deer Creek I did not observe any outcrops of the sedimentary rocks, local drift and flows of lava covering everything up, but on the east side of the latter valley the sedimentary rocks rise above the cover- ing of Java in two or more small ridges. As will be seen by reference to the map, these are nearly on the line of the fault and probably be- long to the dragged strata of the south side. They are Carboniferous sandstones, and contain numerous characteristic fossils, amongst which the following genera are represented: Spirifer, Athyrus, Hemipronites, and Productus. On the trail near the head of the eastern branch of Black-tail-deer Creek some sandstones occur which have also a vertical position, and a strike almost uniform with that of the more westerly outcrops. Hast of this, so far as my knowledge goes, there are no exposures of the rocks of the south side of the fault. The schists.of the north side form the walls of the third canon and appear in Junction Valley and in the lower part of the valley of Kast Fork. MOUNT EVARTS. In the angle between Gardiner River and the Yellowstone is a broad triangular mountain mass comprising an area of about 20 square miles, which is known by people who frequent the Park as Mount Hvarts. This name has been attached to it since 1870. The story of Mr. Evarts’ adventures and suffering is well known, and the fact that his rescue from a horrible death took place in a little valley just back of the sum- mit of this mountain makes the name more than usually appropriate. To the casual observer this mountain may not seem to be one to which he would be ambitious to attach his name; but I am free to say that as an object of interest, either to the tourist or geologist, it has not its equal in the Park, and I am quite sure that those who come once within its shadow will not soon cease to remember it as one of the iOS striking landmarks of the whole land of wonders. The visitor to the springs is constantly confronted ca a gigantic mountain wall that rises on the opposite side of Gardiner River to the height of 2,000 feet, and seems to close him in in a way that is almost oppressive. In the morning light and up to midday this wall is in shadow, and is almost a blank, but as soon as the sun reaches the zenith the ridges of its deeply scored face begin to appear in relief, and we have a chance to study the character of the formations and the very striking work of the erosive agents. From the high angular point that overlooks the junction of the East Fork with the main Gardiner a broad, massive sheet of rhyolitic lava extends back to the right and left across the plateau-like summit. fronting the springs this cap of rhyolite breaks off in a vertical wall nearly 100 feet in height. Just opposite the springs, at the highest point of the mountain, the wall terminates rather abruptly, the lower surface 10 REPORT UNITED STATES GEOLOGICAL SURVEY. rising upon the eroded edges of the Cretaceous sandstones and shales which formed the border of the flat basin into which the molten muss was poured. With the aid of a field-glass the details of the contact be- tween the rhyolite and the Cretaceous strata can be pretty clearly made out, but the curious white line, bordered by a ferruginous belt, which eccurs along the contact, must be examined more closely to be fully un- derstood. North from the point at which the rhyolite terminates, the outline of the mountain sweeps downina bold curve toward the Yellowstone. There is no longer a capping of lava to sustain the sharply escarped edge, but a series of remarkable sheets of dark basaltic lava perform that office. Unlike the rhyolite, which has been flowed as a sheet upon the surface of the Cretaceous strata, these basaltic masses are included between the yielding strata, and if examined carefully may be seen to cross from horizon to horizon, breaking through the beds and pushing them aside, and bending and crushing them in a most remarkable manner. Down on the slopes to the north other masses of intruded rock are exposed, and beyond these the whole wall becomes so broken down and smooth _ that a horseman can ascend with ease. Down by the rivera secondary wall occurs, and this, with an opposing wall on the west side, forms a little eafon through which the river flows. These strata, together with all those visible in the great wall,are Cretaceous. The dips all along are from 5 to 15 degrees to the north as seen from the west side of the river. There is also a dip to the east from the brink of the wall still more marked, and a very little beyond the crest the strata come within the influence of the abrupt fold of the great displacement which passes from northwest to southeast through the mass of the mountain. The dip, as we approach the axis of the fold, becomes vertical, and in places passes beyond 90°. The strata composing the upper half of the great wall are chiefly sandstones, generally rather soft, grayish and y ellowish in color. Interbedded with the sandstones are shales, clays, and lig- nites. The lower part of the slope consists of dark-gray shales, beneath which, in the creek bed, are the sandstones of the Dakota Group. On the 12th of September our party set out on its second trip, the march of the day being from the springs to Junction Valley. Wishing to see as much of Mount Eivarts as possible, I determined to climb the wall at the first accessible point toward the north, visit the basaltic outcrops, and cross the flat summit of the mountain to the mouth of Black- tail-deer Creek. Riding down the steep slopes over the old hot-spring deposits and Cretaceous shales, I crossed the river about a mile Delow the springs, and led my mule up the long , Steep, and cliff-broken slope. Along the river there is a broad bels of sloping ground that forms a sort of talus to the wall; this space is covered with sage and short grass, and is deeply cut by a inultitude of narrow gulches which have been scored out by avalanches from the steeper walls above. In the cliffs, from the base to the summits, the rocks which form the principal outcrop are fine- grained, yellowish sandstones, often quite massive. There are numerous beds of sandy shales, and not infrequently inter- calated lamina of quartzitic sandstone. At the base some of the falling masses contain indistinct impressions of deciduous leaves, together with imperfectly preserved fruits and irregular masses of carbonaceous matter. Throughout the section there are occasional indications of coal, which iS appar ently an impure shaly lignite. The exposures are, however, far from satisfactory. Outcrops of basalt occur, but are obscured by débris. Co“ WG E Za aN AL VEG Ae J3 et N Pad we a era ee A ir —ama\ tA) TA i i LO SZEI \\ ye |! te | es fs \ eave ee SG aa Cretaceous Coal Measures. Plate V.—Intruded basalts, Mount Evarts. es bb Basalts. salts of Mount Evarts. ed ba g tho intrud showin ? Ideal section d Mount Evarts ridge and basaltic masses. a. ¢ Crumpled strat Fault. b a Yellowstone River. Use 2 eae 0 Sr ve a 1 | Plate VI.—Intruded basalts, Mount Evarts. HOLMES. J GEOLOGY OF MOUNT EVARTS. . 11 A sparse growth of stunted pines has taken root in the rocky slope and on the crest of the ridge there are groves of full-grown trees. The examination of the basalts near the summit proved unexpectedly interesting. The masses of this rock are very irregular in thickness, reaching in places 40 and 50 feet, their position in the strata, being very irregular. They lie in rude sheets approximately with the strata, but bearing the strongest evidence of their intrusive character. The irregular bed that outcrops along the crest of the ridge is in places 40 feet in thickness, but generaily falls far short of this. Its position in the strata points very clearly to its intrusive character. It does not lie in any one horizon, but breaks across the strata at all angles, crushing the severed edges back upon themselves as shown in the drawing, Plate V. It rests chiefly in a series of coal shales and sandstones in which are very numerous leaf impressions. The shales are but little changed by contact with the basalt, and where in actual contact are still brittle and crumble under the hammer. The shales above the intruded mass are also but little altered. In the heavier masses this basalt has a rudely columnar structure and weathers down in very small angular blocks. In the thin tongues that have been thrust out from the main mass into the surrounding strata there is a tendency to form small prisms at right angles to the surface, as shown in the figure; while the interior part of these tongues has only a minute irregular jointage. The color of this basalt is, in the weathered surfaces a rusty brown, but when freshly fractured a dark steel gray. It is fine grained and compact and has no crystals distinguishable by the naked eye. The strata which inclose this basalt dip to the northeast at angles of from 10° to 15°, the line of the great fault, which defines their northern limit, being about two miles distant. It seems probable that the intruded basalts may have originated in or rather reached their present position through this fault, the crushing of the strata indicating, generally, an intrusion from that direction. Similar intrusions are very numerous in all the strata bordering the fault line. (See Plate VI.) It may be well in this connection to give another illustration of the intruded basalts which occurs also in the western face of Mount Evaris, but farther south and within a mile of the mouth of the East Fork of Gardiner River, and within about 400 feet of the bed of the main Gardiner. The rock is a pinkish-gray basalt (?) that weathers down in crumbling heaps, but where freshly exposed is an exceedingly compact and fine-grained rock. The mass is about 300 feet long by from 12 to 15 feet thick and appears in the face of a steep wall of dark shales and laminated sandstones. It has been forced in between the yielding strata, folding them up almost at right angles at the ends, as shown in the fig- ure, Plate VI. There is a decided alteration in the contiguous strata; the shales and sandstones for a number of feet beyond the contact with the intruded mass being changed to hard slates and quartzites which break up in minute blocks. Other intrusions occur all along the face of the wall that overlooks the caiions of the East Fork and are especially numerous about the falls and on the south side of the valley. Having followed the crest of the mountain south from the previously described outcrops of basalt, I soon reached the north edge of the great sheet of rhyolite that rests upon the flat part of the summit. The north- ern border of this sheet is pretty thoroughly obscured by soil and drift deposits, and cannot be defined with accuracy, but the exposure on the west front is simply perfect. The whole thickness of the sheet, some 80 or 90 feet, breaks off in a vertical and overhanging cliff. The upper ra 12 REPORT UNITED STATES GEOLOGICAL SURVEY. surface is approximately level; the under surface takes the form of the depression into which it flowed, which, as shown by the section in the cliff face, had a gentle slope from the northern rim to the south. The sandstones dip in the opposite direction, that is, to the north, at an an. gle of about 15°. The ends of these strata had been planed down to a pretty uniform slope before the flow of the rhyolite occurred. The most peculiar and interesting circumstance connected with this flow is the existence of a bed of loosely compacted material that lies between the sandstone floor and the sheet of rhyolite. This bed varies in thickness from 5 to 10 feet. The lower part is deposited upon the somewhat uneven surface of the sandstones, and is composed of a white powder that resembles slacke:l lime in appearance, and is probably a volcanic tuta. The white stratum runs up into a delicate gray stratum, which is succeeded by about 4 feet of fine grained laminated tufaceous sandstones that have the most perfect lines of bedding possible. There is an alternation of white, gray, and dark gray lines shown upon the smooth vertical surface that for perfection of line and delicacy of color could not be rivaled by the pencil of the skilled artist. That these lines indicate planes of bedding is clear, as there is a slight change in the coarseness of the material noticeable in the various layers. The most remarkable fact seems to me to be this, that these lines of color, as delicate as the finest penciling could make them, are continuous throughout the whole length of the wall examined. (PI. VII.) The whiter stratum at the base is not sufficiently compacted to allow the collection of a hand specimen. The grayer layers above have the consistency of asoft argillaceous sandstone, but havea very low specific gravity. Between the gray laminated layers and the base of the rhyo- lites is a zone of peculiar rock that seems to show an imperceptible tran- sition from the ove to the other. Itis quite impossible to tell just where the rock ceases to be an ageregation of grains and becomes a true crys- talline java. This transition rock is dark in color, as is also the lower part of the sheet of rhyolite, and at a little distance looks very much like a basalt. Its weight, however, is not half that of an ordinary basalt, and when examined closely apparently consists of dark and light glossy grains imbedded in a paste of fine gray ash. The coarser lamina below contain a great deal of more or less finely pulverized sanidin. In studying the delicate lamination of these tufaceous deposits one is led te inquire what could have been the method of their deposition. That they are not sub-aerial is evident, for it would be necessary to suppose the entire absence of all winds, as the least irregularity of de- posit would destroy the continuity of thelaminz. It seems more proba- ble that the almost impalpable dust from distant vents has been cast _ by the winds om the surface of deep and quiet waters and been allowed to settle on the bottom beneath. And yet with this explanation it is almest ineredibie that as much as ten feet of such delicate strata could be laid down without including a single particle above the size of a pin- head er without the intrusion of any form of organic body whaiever. The tufaceous stratum slopes at first about 16°, and further south, if it continues beneath the rhyolite, becomes horizontal. At the point ex- amined it has been weathered out to the depth of several feet, allowing the rhyelite ledge to overhang. Similar and still more interesting de- posits underlie the rhyolites of the grand caiion of the Yellowstone, and wili be deseribed in the proper place. The rhyolite of the overlying sheet is quite dark, and by those who have seen it at a distance has been called basalt. It is a dark purplish- gray rhyolite ef moderate weight, and is No. 2 in Captain Dutton’s ee ——= a | aSheet of rhyolite. 6 Finely laminated tufa. ¢Cretaceous sandstones. Drift. Plate VII.— Showing contact of rhyolite cap of Mount Evarts with the Cretaceous sandstones. HOLMES.] GEOLOGY OF MOUNT EVARTS. 13 catalogue. It has a tendency to weather in rude columns, but these are not clearly defined. It doubtless forms a part of the great rhyolitic sheet, the borders of which can befound at a similar level all around the rim of the valley of Gardiner River, and which appears elsewhere fur- ther east. The edges of the sandstone strata which come in contact with the white tufaceous stratum are somewhat discolored as if by metamorph- ism or oxydization of minerals. The section of these strata as given farther on extends from this point directly down the face of the cliffs, reaching Gardiner River at the base of the Mammoth Hot Springs. On the 13th of August we had been forced by continued snow-storms to relinquish work in the Gallatin Mountains, and arrived at the springs preparatory to starting for Bozeman. Onthe14th,accompanied by Dr. Peale, who had just arrived from the Geyser Basin, I determined, not- withstanding the fact that the snow was three or four inches deep, to, examine the strata in the great wall of Mount Evarts. Descending to the river, we passed over, as on a previous occasion, extended bodies ot hot-spring deposits, beneath which, near. the river, a limited outcrop of sandstones occur. These sandstones probably belong to the Dakota Group of the Cretaceous, and consist of 20 to 30 feet in thickness of massive, coarse-grained sandstones that dip beneath the bed of the river at an angle ‘of about 15°. It is probable that these sandstones underlie a oreater part of the drift and sinter-covered slopes of the west side of the valley. Beneath the massive bed of sandstone some laminated beds appear, which doubtless belong also to the Creta- ceous. Crossing the river, we rode for a considerable distance up the gorge- cut talus slope, which is covered with grass and sage. We hitched our animals, as far up as they could be taken, at the height of nearly 1,000 feet above the river bed, just opposite a steep cliff which overhangs a deep gulch. In the vertical part of the cliff are exposed about 200 feet of light-gray argillaceous and sandy shales. From the base of the vertical cliff we climbed, not without consider- able difficulty, as a snow-storm was raging, to the summit of the mount- ain at the northern end of the rhyclite escarpment. Rather imperfect impressions of leaves were found at a number of localities. Professor Lesquereux having examined them, announces that they certainly indi- cate the Cretaceous age of the formation. A small number of rather imperfect fossil shells were found near the top, which are considered by Professor White to represent Upper Cretaceous, and possibly Post-Cre- taceous species. The section, beginning at the top, is as follows: Feet. 1. Drift. PapEUurpL Shy SaniGumenitachiybol seer = is