,! ,geologic ,/ory                      
(                          ,glaci]      
,national ,p>k                          
,cov] ,,*ief ,,m\nta9                   
,special ,bullet9 ,no4 #c               
,,glaci] ,,natural ,,hi/ory             
,,association                           
,price #be ,c5ts                        
,,! ,,geologic ,,/ory                   
(                          ,,glaci]     
,,national ,,p>k                        
,by ,,james ,l4 ,,dyson                 
,head1 ,dep>tm5t ( ,geology & ,geography
                           ,lafayette   
,college#a  ,until rec5tly a geologi/ 0 
visualiz$ by mo/ p z a que] sort ( fell[
 :o w5t ar\nd ! c\ntryside break+ rocks 
) a little hamm]4 ,=tunately1 ! g5]al   
public today has a mu* cle>] picture ( !
 geologi/ & 8 sci5ce1 b !re are /ill _m 
among u :o mi/ak5ly feel t geology is   
some?+ too remote = practical           
application4  ,geology is ! sci5ce ( !  
,e>?4 ,x includes a hi/ory ( our planet 
/>t+ ) its orig91 & a hi/ory ( ! life   

:i* has liv$ ^u x4 ,f x we c det]m9e !  
reason = e feature ( ! l&scape & e rock 
/ructure und]nea? ! surface1 & we c     
fur!r le>n :at processes gave rise to   
!m4  ,practically ev]y?+ to be se5 on ! 
face ( ! ,e>? owes its orig9 directly or
 indirectly to geological processes4 ,^!
 may be gr\p$ into two great categories3
 ,int]nal =ces or ag5ts :i* raise1 l[]1 
b5d1 & break ! ,e>?'s cru/2 & ext]nal1 m
 famili> ag5ts su* z wat]1 w9d1 & ice1  
:i* we> away ! surface & c>ry ! mat]ials
 to ano!r place--ultimately to ! sea4   
,let u consid] a few ( ! products ( ^!  
geologic ag5ts3 7#a7 ,! soil cov]+ mo/ (
 ! l&scape & furni%+ ! plant products   
:i* s]ve z our food2 7#b7 ! solid rock1 
s conspicu\s 9 all m\nta9 ranges2 7#c7 !
 hills1 ! valleys1 & ! m\nta9s2 7#d7 all
 ! /reams1 ponds1 lakes--ev5 ! sea4 ,if 
y live 9 a place :]e man has cov]$ up ! 
rock & ! soil evid5ce ( geological      
processes is yield$ by ! build+s        
!mselves1 :e!r !y be ( /one qu>ri$ f !  
,e>?'s cru/1 or ( brick made f clay4 ,! 

/one & brick are support$ by a framework
 ( /eel orig9ally tak5 f a m9e 9 ! =m ( 
iron ore4 ,! concrete & asphalt ( !     
roads came f rocks )9 ! ,e>?1 z did e   
drop ( gasol9e :i* plays s vital a "p 9 
_w affairs today4 ,ev5 ^? commonplaces (
 ,am]ican life1 ! bottle & ! t9 c1 are  
products ( geology4 ,z y read ?is y ne$ 
look only at y\r wat* or p]haps an item 
( jewelry :i* y we> to see some?+--gold1
 silv]1 plat9um1 a diamond or o!r gem   
/one--:i* is a "p ( geology4  ,?us1 f "h
 x is a %ort /ep to ! realization t a   
numb] ( geologic processes & ag5ts work+
 ov] long p]iods ( "t h giv5 rise to    
innum]able features & /ructures rang+ f 
! l(tie/ m\nta9s d[n to ! smalle/ hills 
& valleys2 f ! soil :i* gr[s our food to
 ! gasol9e & coal :i* fe$ our indu/ries2
 f our huge iron ore deposits d[n to !  
mu* small]1 b n[ no less significant1   
deposits ( uranium4  ,h[ is all ?is     
relat$ to a national p>k8 ,n[h]e )9 our 
l& c ! accompli%m5ts ( ! great          
geological processes1 or _! pres5t-day  

op]ation1 be se5 to bett] advantage ?an 
9 _m ( our national p>ks & monum5ts4 ,9 
fact1 x is = ?is reason pr9cipally t _m 
( !m 7 e/abli%$4 ,notable is ,gr&       
,canyon ,national ,p>k1 conta9+ ! mo/   
spectacul> "p ( ! ,colorado's mile-deep 
canyon cut dur+ ! pa/ million or s ye>s 
?r\gh a s]ies ( rocks :i* !mselves      
record a billion or m ye>s ( ,e>?       
hi/ory4 ,m\nt ,ra9i] is ! l>ge/ volcano 
9 ! ,unit$ ,/ates4 ,on x glaci]s are n[ 
we>+ away mat]ials =m]ly extrud$ & pil$ 
up to spectacul> height by volcanic     
=ces4 ,crat] ,lake lies 9 ! sunk5 ?roat 
( a volcano :i* at "o "t probably rival$
 ,ra9i] 9 size4 ,9 ,c>lsbad ,cav]ns &   
,mammo? ,cave ,national ,p>ks are two ( 
! _w's l>ge/ cav]ns :i* cle>ly          
demon/rate ! trem5d\s effectiv5ess (    
subsurface wat] 9 dissolv+ lime/one4    
,bryce ,canyon & ,zion ,national ,p>ks &
 ! ,badl&s ,national ,monum5t illu/rat$ 
on a mu* small] b no less spectacul>    
scale ?an ! ,gr& ,canyon ! wond]ful     
erosive p[] ( runn+ wat]4 ,9 ,gr& ,teton

 "o c see a huge block ( ! cru/ :i* has 
be5 rais$ ?\s&s ( feet along a          
high-angle fault1 & at ,lass5 ,peak 9   
,cali=nia & ,crat]s ( ! ,moon 9 ,idaho  
!re are exhibit$ "s ( ! mo/ rec5t       
volcanic features nor? ( ! ,rio ,gr&e4  
,despite ,yell[/one's wildlife & fi%+ x 
is be/ kn[n p]haps = its geys]s4 ,?is   
brief li/ is by no means complete1 =    
some?+ ( prime geologic int]e/ c be f\nd
 9 almo/ e national p>k & monum5t4  ,n[ 
we come to ,glaci] ,national ,p>k4 ,)9  
its b\nd>ies !re p]haps is exhibit$ a   
great] v>iety ( geologic features ?an 9 
any ( ! o!rs4 ,mu* ( ! p>k lies above   
timb]l9e s t ! rocks :i* comprise its   
m\nta9s are expos$ to view4 ,held )9 ^! 
sup]b m\nta9s is an ent]ta9+ geologic   
/ory :i* !y are anxi\s & will+ to tell  
u4 ,all we ne$ to d is unlock ! door ) !
 key ! geologi/ gives u & !n g see =    
ourselves4 ,:y d ! m\nta9s rise s       
precipit\sly above ! pla9s8 ,:at is t   
conspicu\s black b& across ! faces ( s  
_m ( ! peaks1 & h[ did x get !re8 ,:y   

are "s ( ! rocks s r$8 ,! answ]s to ^! &
 o!r que/ions come out z ! geologic /ory
 unfolds4 ,! ,am]ican p are int]e/$ 9   
?is /ory = !y realize t to und]/& :at !y
 see is to increase _! enjoym5t         
?\s&fold4                               
,*>t ( ,geologic ,"t   7,,= ,a          
,,*ronological ,,ord] ,,( ,,ev5ts1 ,,!  
,,*>t ,,%\ld ,,be ,,read ,,f            
,,bottom ,,to ,,top7       ,,eras       
,,p]iods        ,,dates                 
,,ev5ts ,,9 ,,glaci] ,,p>k ,,area       
,,c5ozoic                       ,!      
,pres5t        ,po/ ,glacial            
,erosion ( ! m\nta9s2 =mation (         
alluvial fans & talus cones4            
#ae1jjj ,b4,c4        ,plei/oc5e        
,bir? ( mod]n glaci]s4                  
,appe>ance ( pres5t =e/s4               
#a1jjj1jjj ,b4,c4        ,plioc5e       
,ext5sive glaciation4 ,=mation ( lakes1 
wat]falls1 horn peaks1 cirques4 ,valleys
                                        
sc\r$ deeply by glaci]s4        ,mioc5e 
,disappe>ance ( =e/s4        ,oligoc5e  

,m\nta9s worn d[n1 rais$1 erod$ aga94   
,eoc5e                      ,lewis      
ov]?ru/ probably occurr$ e>ly           
9 ,eoc5e4                   #eh1jjj1jjj 
,b4,c4   ,,mesozoic                     
,great m\nta9 build+ 7,rocky ,m\nta9    
revolution7 by =ces :i* ev5tually       
=m$ ,lewis ov]?ru/4 ,sea )drew &        
nev] aga9 return$4 ,?ick accumulation   
( m>9e s$im5ts4 ,inv]tebrates           
abundant 9 sea4 ,expansion ( ! sea4     
,cretace\s                  #abg1jjj1jjj
 ,b4,c4        ,jurassic                
,triassic                    ,d9osaurs  
probably inhabit$ p>k &                 
ne>by area4                             
#ahb1jjj1jjj ,b4,c4   ,,paleozoic       
,seas cov]$ region dur+ mu* ( era4      
,p]mian        ,c>bonif]\s              
#bee1jjj1jjj ,b4,c4        ,devonian    
,silurian        ,ordovician            
,cambrian                  #eaj1jjj1jjj 
,b4,c4   ,,prot]ozoic                   
,sea )drew & region 0 erod$ at end      
( era4                                  

,area cov]$ by sea 9 :i* ,belt          
s$im5ts 7 deposit$4                     
,algae liv$ 9 sea4 ,intrusions 7diorite 
sill & dikes7 f fl[s 7,purcell7 (       
igne\s mat]ial4   ,,ar*eozoic           
#b1aaj1jjj1jjj ,b4,c4  8    ,,eras1     
,,p]iods1 ,,& ,,dates ,,9 ,,?is ,,*>t   
,,are ,,9 ,,accordance ,,) ,,^?    ,,:i*
 ,,h ,,be5 ,,adopt$ ,,z ,,(ficial ,,by  
,,! ,,national ,,p>k ,,s]vice4          
,! ,/ory ,beg9s   ,! mo/ /rik+ feature (
 ! m\nta9s--c]ta9ly ! "o :i* comes fir/ 
to a visitor's att5tion--is ! color b&+4
 ,no matt] :]e "o looks ?is feature     
greets 8 view4 ,if he ent]s ! p>k at !  
,/4 ,m>y ,entrance1 !re ahead on ! sides
 ( ,s+le%ot & ,ea/ ,flattop ,m\nta9s are
 :ite & purple b&s4 ,%\ld he ent] fir/ !
 ,swiftcurr5t ,valley1 he w\ld soon note
 ! b&+ 9 ! m\nta9s ly+ to 8 "r & left1 &
 f9ally culm9at+ 9 ! precipit\s ,g>d5   
,wall at ! head ( ! valley4 ,! visitor  
soon realizes t e m\nta9 )9 ! p>k is    
compos$ ( rock lay]s ( v>i\s colors4 ,) 
v few exceptions ^! /rata are ( s$im5t>y

 orig92 t is1 !y accumulat$ by          
depositions ( muds & s&s 9 a body ( wat]
 & are n[ ma9ly lime/ones1 %ales1 &     
s&/ones4 ,^! s$im5t>y rocks all belong  
to a s+le l>ge unit kn[n z ! ,belt      
s]ies1 s nam$ because ( exposures 9 !   
,little ,belt & ,big ,belt ,m\nta9s f>!r
 s\? 9 ,montana4 ,9 ,glaci] ,national   
,p>k ^! rocks1 :i* h a maximum ?ickness 
( m ?an #bj1jjj feet1 are 9 ! =m ( a    
l>ge syncl9e 7d[nfold71 ! ea/ & we/     
edges ( :i* =m ! cre/s ( ! ,lewis &     
,liv+/one ,ranges 7,figure #c;,d74      
,?r\gh\t ! l>ge area ( we/]n ,montana1  
nor!rn ,idaho1 & s\!rn ,briti% ,columbia
 :]e ,belt rocks occur1 !y are important
 m\nta9-mak]s4 ,9 addition to ! ranges  
already m5tion$ !y are ! pr9cipal rocks 
9 _m o!rs1 includ+ ! ,mission1 ,swan1 & 
,fla!ad 9 ! region s\? ( ,glaci] ,p>k2 !
 ,bitt]root & ,coeur d',al5e betwe5     
,idaho & ,montana2 & ! ,purcell 9       
,briti% ,columbia4 ,fur!r1 rocks (      
simil> age =m ! core ( ! ,u9ta ,range 9 
,utah & ! l[] section ( ! ,gr& ,canyon 9

 ,arizona4  ,dur+ ! ,prot]ozoic ,era (  
,e>? hi/ory a long1 n>r[ section ( ,nor?
 ,am]ica ext5d+ f ! ,arctic ,ocean      
s\?w>d1 probably z f> z ,arizona & s\!rn
 ,cali=nia1 sl[ly sank to =m a l>ge1    
%all[1 sea-fill$ tr\gh kn[n z a         
geosyncl9e 7,figure #a74 ,/reams f      
adjac5t l&s c>ri$ muds & s&s into ! sea1
 at times almo/ completely fill+ x4     
,inasmu* z ?\s&s ( feet ( s$im5ts 7     
deposit$1 ! geosyncl9e mu/ h cont9u$ to 
s9k ?r\gh\t ! p]iod ( s$im5tation4      
,ev5tually ! muds 7 compact$ into %ales1
 or lime/ones if !y conta9$ a lot (     
lime1 & ! s&s into s&/ones4 ,^! are !   
rocks we n[ "k z ! ,belt s]ies4 ,!      
surfaces ( _m ( ! s&/one lay]s are cov]$
 ) ripple m>ks :i* c\ld h be5 made only 
by wave & curr5t action 9 %all[ wat]4   
,mudcracks on _m ( ! %ale b$s prove t at
 times ! s$im5ts1 probably ne> ! m\?s ( 
riv]s 7 expos$ to ! air long en\gh to   
dry out4 ,great ?icknesses ( lime/one & 
num]\s fossils ( calc>e\s algae1        
primitive m>9e plants1 are evid5ces t ! 

body ( wat] 0 a sea4  ,,figure #a4      
,,belt ,,geosyncl9e  ,?r\gh\t ! geologic
 pa/ ! appe>ance & disappe>ance ( seas  
on ! cont95ts h be5 frequ5t ev5ts4 ,9   
fact su* *anges are sl[ly tak+ place ev5
 today4 ,hudson ,bay & ! ,baltic & ,nor?
 ,seas are examples ( %all[ seas situat$
 on ! cont95ts4 ,! area ar\nd ,hudson   
,bay is ris+2 z atte/$ by ! fact t "s ( 
! fi% weirs con/ruct$ 9 wat] along !    
%ore dur+ ! pa/ sev]al hundr$ ye>s are  
n[ a consid]able di/ance inl&4 ,we "k   
also t our ,atlantic coa/ has be5       
subsid+ = a numb] ( ye>s at an annual   
rate ( ab\t #j4jb feet4 ,to be sure1 ^! 
movem5ts are sl[1 b if cont9u$ ov] a    
long p]iod !y might conceivably make "s 
r pr(\nd *anges1 ev5 z ! bir? & dea? ( !
 ,belt sea4  ,)9 ,glaci] ,national ,p>k 
! ,belt s]ies is divid$ on ! basis (    
li?ologic diff]5ces into six di/9ct     
=mations4 ,because ea* has a *>act]i/ic 
color1 ^! =mations c easily be id5tifi$1
 (t5 f di/ances ( sev]al miles4 ,usually
 two1 sometimes ?ree or f\r1 ( !m       

comprise a s+le m\nta91 ! olde/ always  
at ! m\nta9 base & ! y\nge/ on ! summit1
 ?is be+ ! relative position 9 :i* !y 7 
deposit$ 9 ! =m ( s$im5t4  ,illu/ration3
 ,,mud ,,cracks ,,on ,a ,,lay] ,,( ,,!  
,,appekunny ,,=mation                   
7,,photo ,,by ,c4 ,l4 ,,f5ton4 ,,our    
,,amaz+ ,,e>?4 ,,d\bl$ay ,,& ,,co47     
,illu/ration3 ,,ripple ,,m>ks ,,on ,a   
,,lay] ,,( ,,! ,,%ep>d ,,=mation ,,ne>  
,,logan ,,pass4 ,,_! ,,assymmetrical    
,,=m ,,indicates ,,=mation ,,by         
,,curr5ts ,,9 ,,%all[ ,,wat]4           
7,,dyson ,,photo7                       
,! ,belt ,=mations                      
,,altyn ,,=mation4  ,?is is ! olde/ ( ! 
sev]al =mations & ?us occupies a        
/ratigraphic position at ! base ( !     
entire s]ies4 ,x is compos$ ma9ly ( s&y 
dolomites 7magnesian lime/ones7 &       
lime/ones :i* wea!r to a light buff     
color4 ,x outcrops all along ! base ( ! 
ea/]n front ( ! ,lewis ,range &         
comprises ! entire block ( ,*ief        
,m\nta94 ,because ( its comp>atively    

great resi/ance to wea!r+ & erosion x   
usually =ms a conspicu\s ridge or t]race
 :]ev] x crosses a valley4 ,9 !         
,swiftcurr5t ,valley x =ms ! dam :i*    
holds 9 ,swiftcurr5t ,lake & creates    
,swiftcurr5t ,falls4 ,9 ,two ,m$ic9e    
,valley ! highway crosses a simil>      
t]race :i* gives rise also to ,trick    
,falls4 ,9 ! ,/4 ,m>y ,valley x creates 
! ,n>r[s & =ms ! impos+ wall 9 lee ( :i*
 ,ea/ ,glaci] ,campgr\nd is locat$4 ,!  
rock ( ?is =mation c be/ be exam9$ on ! 
ridge imm$iately ea/ ( ,_m ,glaci]      
,hotel 7betwe5 hotel & p>k+ lot7 & above
 ,swiftcurr5t ,falls4 ,its av]age       
?ickness is ab\t #b1cjj feet4           
,,appekunny ,,=mation4  ,ly+ on top ( ! 
,altyn are #c1jjj or m feet ( prevail+  
gre5i% %ales & argillites#b compris+ !  
,appekunny =mation4 ,slabs ( ^! rocks1  
because ( _! great h>dness1 h be5 us$ z 
flag/ones 9 ! walks at ! ,_m ,glaci]    
,rang] ,/ation & adjac5t ,p>k ,s]vice   
resid5tial area4 ,mud cracks & ripple   
m>ks are common4 ,! =mation is prom95t  

on ! side ( ,s+le%ot ,m\nta9 ne> ! ,/4  
,m>y entrance to ! p>k1 & ev]y:]e       
imm$iately ov]ly+ ! light]-hu$ ,altyn   
along ! ea/ edge ( ! ,lewis ,range :]e1 
especially :5 se5 f a di/ance1 x appe>s 
to h a purpli% color4 ,x also outcrops  
along ! we/]n base ( ! ,liv+/one ,range 
7,figure #c;,d71 b su* exposures are z a
 rule obscur$ by a cov] ( d5se =e/4     
,accessible outcrops c readily be exam9$
 along ,go+-to-!-,sun ,highway = sev]al 
miles ea/ ( ,sun ,po9t & ne> ,mc,donald 
,falls1 & also along ! l[] "p ( !       
,gr9nell ,glaci] trail4                 
,,gr9nell ,,=mation4  ,because ( _!     
dom9antly r$ color1 ! %aly argillites   
:i* comprise ! bulk ( ?is =mation are ! 
mo/ conspicu\s rocks 9 ! p>k4 ,!y lie   
imm$iately on top ( ! ,appekunny &      
al?\gh _! ?ickness v>ies consid]ably x  
is great] ?an #c1jjj feet 9 sev]al      
localities4 ,int]b$d$ ) ! r$ argillites 
are ?9 :ite lay]s ( qu>tzite1 a =m]     
s&/one :i* has be5 conv]t$ by pressure  
into an extraord9>ily h>d1 d5se rock4   

,mud cracks1 ripple & curr5t m>ks1      
ra9drop impressions1 & o!r features made
 :ile ! s$im5ts 7 accumulat+ are common4
 ,! r$ color is due to abundant iron    
oxide occurr+ ma9ly z a cem5t betwe5 !  
s& & mud gra9s4 ,all ! rocks ( ,glaci]  
,p>k conta9 "s iron1 or r conta9        
iron-be>+ m9]als4 ,^! m9]als h v>i\s    
colors unless !y h be5 oxidiz$1 9 :i*   
case ! color is r$ or br[n4 ,oxidation (
 ! ,gr9nell =mation probably took place 
:ile ! mud 0 accumulat+ & dur+ ^? p]iods
 :5 x 0 expos$ to ! atmosph]e4 ,at su*  
times also ! mud dri$ & crack$1 ! m>ks (
 :i* are s prom95t on ! surfaces ( !    
lay]s today4  ,! ,gr9nell =mation seems 
to be ev]y:]e4 ,9 ! ,_m ,glaci] region x
 comprises ! bulk ( ,gr9nell ,po9t1     
,altyn ,peak1 & ,m\nt ,all51 & is no    
less /rik+ 9 ! bases ( ,m\nt ,wilbur & !
 ,g>d5 ,wall4 ,pt>migan ,tunnel is      
drill$ ?r\gh x1 & ! trails to ,gr9nell  
,glaci]1 ,crack] & ,iceb]g ,lakes cross 
x4 ,r$rock ,falls1 on ! trail to        
,swiftcurr5t ,pass1 & ,pt>migan ,falls  

on ! ,iceb]g ,lake trail drop ov] sev]al
 ( its highly color$ lay]s4  ,f !       
,blackfeet ,highway on top ( ,two       
,m$ic9e ,ridge "o c see ! d>k r$ rocks (
 ?is =mation capp+ ! summits ( ,ris+    
,wolf & ,r$ ,m\nta9s4 ,ev5 f ! valley   
floor x is j z noticeable4 ,s9opah      
,m\nta9 /&+ alone & impressive across ! 
lake f ,two ,m$ic9e ,*alets c>ries ! r$ 
bann] ( ! ,gr9nell =mation4  ,^! r$     
rocks con/itute an important sc5ic      
feature = _m miles along ,go+-to-!-,sun 
,highway4 ,if "o beg9s 8 trip on ?is    
highway at its ea/ entrance he soon f9ds
 himself 9 ! mid/ ( a gr\p ( impos+ r$  
peaks--,goat & ,go+-to-!-,sun on ! "r1  
,r$ ,eagle & ,mahtotopa on ! left4 ,!   
road crosses ! =mation along a mile & a 
half /ret* j we/ ( ,b>+ ,creek bridge4  
,innum]able loose slabs ( r$ rock along 
! side ( ! road conta9 excell5t mud     
cracks & ripple m>ks4 ,ne> ,avalan*e    
creek on ! we/ side ( ,logan ,pass !    
highway crosses ! ,gr9nell :]e x comes  
to ! surface on ! we/]n limb ( ! big    

syncl9e4  ,! =mation is well expos$ 9 ! 
vic9ity ( ,sp]ry ,*alet & ,glaci]4 ,x   
=ms all ! m\nta9s surr\nd+ ! bas9 9 :i* 
! *alet is locat$1 & ! trail f *alet to 
glaci] lies :olly on x4 ,at ! glaci]    
int5sely fold$ :ite qu>tzite lay]s & r$ 
argillites are v conspicu\s4  ,! visitor
 c readily trace ! ,gr9nell f place to  
place ?r\gh\t ! entire p>k area1 & c ?us
 easily visualize t x z well z all o!r  
=mations at "o "t fill$ ! int]v5+ spaces
 betwe5 ! m\nta9s4 7,see color ( cov]   
pages47                                 
,,siyeh ,,=mation4  ,next above !       
,gr9nell is a ?ick lime/one =mation :i*1
 because ( its wea!r$ buff color1 /&s   
out 9 %>p contra/ to ! r$ b$s ^u :i* x  
re/s4 ,x is ! greate/ cliff-mak] 9 ! p>k
 & 9 sev]al places its entire ?ickness (
 #d1jjj feet may be expos$ 9 a s+le     
ne>ly v]tical cliff4 ,s9ce x is y\ng]   
?an ! ?ree prec$+ =mations1 x is conf9$ 
ma9ly to ! high] elevations1 capp+ _m ( 
! l(tie/ peaks )9 ! ,lewis & ,liv+/one  
,ranges4 ,9 ! ,_m ,glaci] area su* peaks

 are ,m\nt ,g\ld & ! ,g>d5 ,wall1 ,m\nts
 ,siyeh1 ,gr9nell1 ,all51 ,wilbur1 &    
,h5kel4 ,a numb] ( o!rs1 includ+ ,little
 ,*ief1 ,jackson1 ,gunsight1 ,fusillade1
 ,go+-to-!-,sun1 ,piegan1 ,pollock1     
,cannon1 & ,heav5s ,peak1 are visible f 
,go+-to-!-,sun ,highway4 ,! huge        
peaks--,k9n]ly1 ,k9tla1 ,c>t]1 &        
,ra9b[--:i* /& gu>d at ! heads ( ,k9tla 
& ,b[man ,lakes are compos$ ( ! ,siyeh4 
,! li/ also includes ,clevel&1 highe/ & 
l>ge/ ( all4  ,illu/ration3 ,,algae     
,,colonies ,,9 ,,siyeh ,,lime/one ,,ne> 
,,gr9nell ,,glaci]4                     
7,,dyson ,,photo7  ,illu/ration3 ,,g5tly
 ,,tilt$ ,,/rata ,,( ,,! ,,siyeh        
,,=mation ,,9 ,,gr9nell ,,m\nta94       
7,,dyson ,,photo7  ,)9 ! ,siyeh !re is a
 b$1 av]ag+ ab\t #fj feet ?ick1 compos$ 
almo/ entirely ( fossil algae :i*       
app>5tly =m$ an ext5sive reef or        
bio/rome on ! floor ( ! %all[ ,belt     
,sea4 ,! algae colonies are 9 ! =m (    
r\nd$ masses up to sev]al feet 9 diamet]
 & be> a crude resemblance ext]nally &  

int]nally to a head ( lettuce or        
cabbage4 ,geologi/s "k ^! algae by !    
g5us "n ,coll5ia4 ,because ( ! r\nd$ &  
smoo!d surfaces on ^! colonies1 m\nta9  
climb]s frequ5tly f9d ! reef difficult  
to cross4 ,x appe>s z a di/9ct light    
gray horizontal b& on ! ea/ face ( ,m\nt
 ,wilbur ab\t midway betwe5 ! base ( !  
cliff & ! peak's summit1 :]e x c easily 
be se5 f ,_m ,glaci] ,hotel &           
,swiftcurr5t ,camp4 ,x is also          
disc]nible on ! ,p9nacle ,wall above    
,iceb]g ,lake & 9 ,m\nt ,gr9nell4 ,!    
,swiftcurr5t ,pass trail crosses x j ea/
 ( ! pass1 & x is also expos$ along     
,go+-to-!-,sun ,highway bel[ ! big      
swit*back on ! we/ side ( ,logan ,pass  
:]e att5tion is direct$ to x by a sign4 
,unwea!r$ portions ( ! reef rock are    
light blue4 ,a simil> b ?9n] reef       
outcrops at ,logan ,pass ne> ! />t ( !  
,hidd5 ,lake trail4 ,al?\gh mo/ ( !     
fossil algae occur 9 ! ,siyeh !y are    
pres5t 9 ! y\ng] =mations & also 9 !    
,altyn4 ,o!r ?an algae ! only und\bt$   

fossils ( ! ,belt s]ies )9 ,glaci]      
,national ,p>k are burr[s probably made 
by worms4 ,!y are r>e & are re/rict$    
ma9ly to ! ,siyeh =mation4              
,illu/ration3 ,,fossil ,,algae ,,9      
,,siyeh ,,=mation1 ,,hole-,,9-,,!-,,wall
 ,,bas94      7,,! ,,rock ,,book ,,by   
,c4 ,l4 ,,f5ton ,,& ,m4 ,a4 ,,f5ton1    
,,d\bl$ay ,,& ,,co47  ,at ! top ( !     
,siyeh are sev]al hundr$ feet ( s&y &   
%aly b$s1 mo/ly r$di% 9 color1 gr\p$ by 
"s geologi/s into a di/9ct =mation kn[n 
z ! ,spokane4 ,at ,logan ,pass x is ab\t
 #gjj feet ?ick & is well expos$ 9 ! l[]
 p>ts ( ,clem5ts & ,reynolds ,m\nta9s1 &
 at ! site ( ! =m] ,clem5ts ,glaci]4    
,,%ep>d ,,=mation4  ,sev]al hundr$ feet 
( limy b$s :i* wea!r yell[-br[n lie on  
top ( ! ,siyeh4 ,al?\gh nam$ = outcrops 
on ! cliff above ,%ep>d ,glaci] 7s\? (  
,/oney ,indian ,pass & ne> ! site ( !   
old ,fifty-,m\nta9 t5t camp7 ! =mation  
is expos$ on ! summit ( ,swiftcurr5t    
,m\nta9 at ! head ( ,swiftcurr5t        
,valley1 on ,reynolds & ,clem5ts        

,m\nta9s ne> ,logan ,pass1 & on ,citadel
 & ,almo/-a-,dog1 visible f             
,go+-to-!-,sun ,highway 9 ,/4 ,m>y      
,valley4 ,! =mation is replete ) mud    
cracks & ripple m>ks4 ,"s rock surfaces 
exhibit two & ?ree sets ( ! latt]4      
,,k9tla ,,=mation4  ,^! b$s h ! same    
bright r$ color z ^? ( ! ,gr9nell4      
,h[ev]1 because !y are ! y\nge/ rocks ( 
! ,belt s]ies !y outcrop only on a few  
m\nta9tops1 & inasmu* z ^! are ma9ly 9 !
 nor?we/ "p ( ! p>k1 comp>atively few p 
h notic$ ?is =mation4 ,visitors to      
,cam]on ,lake 9 ,wat]ton ,lakes         
,national ,p>k c see x 9 ! r$ nor? wall 
( ,m\nt ,cu/]4 ,! m\nta9s ar\nd colorful
 ,b\ld] ,pass & ,hole-9-!-,wall ,bas9   
are likewise compos$ ( x4  ,)9 ! rocks (
 ?is =mation !re is a great abundance ( 
small cubes believ$ to be ca/s ( salt   
cry/als :i* =m$ :5 ! s$im5ts 7          
accumulat+4 ,_! pres5ce indicates an    
arid climate & int5sive evaporation ( ! 
sea1 simil> to ! condition at ,great    
,salt ,lake today4                      

,igne\s ,rocks ( ! ,belt ,s]ies   ,n all
 ( ,glaci] ,p>k's rocks accumulat$ sl[ly
 & quietly z s$im5t 9 a body ( wat]4 ,at
 _m places1 int]b$d$ ) & cutt+ across ! 
s$im5ts1 !re are bodies ( igne\s rock   
:i* rea*$ _! pres5t position 9 ! =m (   
hot molt5 mat]ial =c$ up f deep )9 !    
cru/4  ,illu/ration3 ,,column> ,,section
 ,,( ,,belt ,,rocks                     
,,prot]ozoic    ,,k9tla                 
#hfj'       ,r$ argillite   ,,%ep>d     
#fjj'        ,buff lime/one   ,,purcell 
#bej'        ,black lava   ,,siyeh      
#djjj'       ,d>k diorite bord]$ by :ite
 alt]$                                  
lime/one                                
,blue lime/one4 ,wea!rs buff   ,,gr9nell
        #afjj-cjjj'     ,r$ argillite & 
:ite qu>tzite   ,,appekunny             
#bejj'       ,gre5 argillite4 ,"s :ite  
qu>tzite   ,,altyn             #bcjj'   
,gray lime/one4 ,wea!rs buff            
,,purcell ,,lava4  ,soon aft] ! y\nge/  
lay]s ( ,siyeh lime/one _h accumulat$ on
 ! floor ( ! sea & :ile !y 7 /ill "u    

wat]1 a mass ( molt5 rock 0 squeez$ up f
 f> bel[ & extrud$ 9 ! =m ( a subm>9e   
lava fl[ ov] ! rec5tly accumulat$       
s$im5ts4 ,sev]al times ?is lava p\r$ out
 =m+ a total ?ickness v>y+ betwe5 #ej & 
#bge feet4 ,"o ( ! be/ exposures is on !
 we/ side ( ,swiftcurr5t ,pass & 9      
,granite ,p>k j we/ & nor?we/ ( ! *alet4
 ,9 fact x is ?is lava fl[ :i* gives !  
"n1 albeit wrongly1 to ,granite ,p>k4 ,!
 mat]ial ( ! fl[ is v f9e-gra9$ & d>k   
7basic71 9 contra/ to ! light color &   
co>se gra9 ( granite4 ,none!less1 _m    
prospectors are wont to call e igne\s   
rock1 reg>dless ( its composition1 a    
granite4 ,a numb] ( ellipsoidal         
/ructures 7pill[s7 up to two feet 9     
diamet] )9 ?is lava indicate t x 0      
extrud$ "u wat]4 ,! ,purcell is ?icke/ 9
 ! vic9ity ( ,b\ld] ,pass1 :]e ! trail  
trav]ses its ropy & /r+y surface = a    
di/ance ( sev]al hundr$ y>ds4  ,lat]1   
aft] ! ,%ep>d & "p ( ! ,k9tla =mation 7 
laid d[n on top ( ! ,purcell1 ano!r     
simil> fl[ spread ov] ! sea floor4      

,,diorite ,,sill4  ,few p]sons visit !  
p>k )\t notic+ ! pron\nc$ black lay]1 )9
 ! ,siyeh =mation1 pres5t on _m ( ! high
 peaks4 ,x is mo/ 9 evid5ce on ! face ( 
! ,g>d5 ,wall view$ f ! vic9ity ( ,_m   
,glaci] ,hotel1 al?\gh x is pla9ly      
visible also 9 ,m\nt ,wilbur & ! wall   
above ,iceb]g ,lake4 ,pass5g]s on !     
,wat]ton ,lake laun* c see x cutt+      
across ! /up5d\s nor? face ( ,m\nt      
,clevel&4 ,f ,go+-to-!-,sun ,highway x c
 be se5 on ,mahtotopa1 ,little ,*ief1   
,citadel1 ,piegan1 & ,go+-to-!-,sun     
,m\nta9s1 & on ! we/ side ( ! ,g>d5     
,wall1 :]e x also =ms ! cap ( ,hay/ack  
,butte4 ,x is ev]y:]e ab\t #ajj feet    
?ick1 & ?us c be us$ z a v accurate     
scale = det]m9+ ! height ( m\nta9s on   
:i* x is disc]nible4  ,?is impos+ lay] (
 rock1 unlike ! lava1 nev] rea*$ !      
surface 9 a molt5 /ate1 b 0 intrud$     
betwe5 b$s ( s$im5t>y rock & ?us became 
a sill in/ead ( a fl[4 ,we ne$ only a   
glance to det]m9e its intrusive nature4 
,:]ev] x occurs x is bord]$ at top &    

bottom by ?9n] gray lay]s4 ,^! are      
,siyeh lime/one :i* 0 *ang$ to m>ble by 
! trem5d\s heat ( ! diorite dur+ its    
intrusion4 ,?is effect is t]m$ contact  
metamorphism by geologi/s4 ,because ?is 
contact-metamorphos$ zone is at bo? top 
& bottom ( ! sill we "k ! latt] 0       
intrud$ into ! adjac5t rocks4 ,lava     
fl[s1 ev5 ?\gh cov]$ lat] by s$im5ts1 ( 
c\rse alt] only ! und]ly+ rocks4        
,illu/ration3 ,,! ,,g>d5 ,,wall ,,&     
,,gr9nell ,,glaci]4 ,,! ,,wall ,,is     
,,compos$ ,,( ,,siyeh ,,lime/one ,,above
 ,,! ,,level ,,( ,,! ,,glaci] ,,& ,,!   
,,gr9nell ,,=mation ,,bel[ ,,x4         
7,,dyson ,,photo7  ,! sill c readily be 
exam9$ 9 a numb] ( places :]e trails    
cross x1 notably at ,swiftcurr5t &      
,piegan ,passes1 & nor? ( ,granite ,p>k 
ne> ,ah]n ,pass4 ,b n[h]e is x z        
accessible z on ,logan ,pass4 ,x lies   
b5ea? ! p>k+ lot at a dep? ( only a few 
feet1 & is expos$ on bo? sides ( ! pass4
 ,to inspect x1 "o ne$ walk only ab\t   
#bjj y>ds along ! trail lead+ to        

,granite ,p>k4 ,9 a di/ance ( less ?an  
#ajj feet ! trail trav]ses f fre% ,siyeh
 lime/one across ! entire alt]$         
7contact-metamorphos$7 zone1 "h #ab to  
#bj feet wide1 into ! c5t] ( ! sill4    
,all p>ts ( ! sill & adjac5t rocks c    
readily be exam9$ & /udi$ 9 detail at   
?is site4  ,illu/ration3 ,,top ,,( ,,!  
,,diorite ,,sill ,,( ,,blackfoot        
,,glaci]4 ,,! ,,man ,,is ,,/&+ ,,on ,,! 
,,sill4 ,,light ,,rock ,,ov]ly+ ,,sill  
,,is ,,contact-,,metamorphos$ ,,siyeh   
,,lime/one4                             
7,,dyson ,,photo7  ,a numb] ( dikes#c ( 
,belt age1 "s ( :i* und\bt$ly 7 fe$]s to
 ! sill & fl[s1 cut v]tically up ?r\gh !
 s$im5t>y =mations4 ,"s ( ! dikes are   
less resi/ant to wea!r+ & erosion ?an ! 
rocks surr\nd+ !m2 consequ5tly _! m     
rapid removal results 9 ! =mation ( n>r[
 v]tical *imneys or recesses :i* appe> z
 sn[-fill$ *utes on ! m\nta9sides 9 spr+
 & e>ly summ]4 ,su* a feature almo/     
inv>iably indicates ! pres5ce ( a dike4 
,f ,_m ,glaci] ,hotel "o ( ^! c be se5  

on ! r$ m\nta9 9 front ( ,m\nt ,wilbur4 
,ano!r1 #a1ejj feet high1 transects !   
,p9nacle ,wall at ! outlet ( ,iceb]g    
,lake4 ,! dike :i* =ms ?is impressive   
*ute is less ?an ?irty feet wide4 ,?\gh 
n s conspicu\s z ! sills "s ( ^! dikes  
are ( int]e/ because !y conta9 v>i\s ore
 m9]als1 pr9cipally copp]1 :i* today =m 
small deposits along _! bord]s4 ,ab\t ! 
beg9n+ ( ! c5tury ^! 7 responsible = a  
%ort-liv$ m9+ boom1 ! be/ kn[n ve/ige ( 
:i* is ! rema9s ( ! mill at ,crack]     
,lake4 ,! old ,crack] ,m9e1 ) entrance  
n[ cav$ 91 0 driv5 along a dike :i* has 
a wid? ( ov] #ajj feet4  ,f ! boat l&+  
at ! head ( ,joseph9e ,lake ! dump (    
ano!r m9e appe>s z a t9y gray-gre5 m\nd 
on a n>r[ %elf high on ! precipit\s wall
 ( ,gr9nell ,po9t4 ,l ! ,crack] ,m9e ?is
 "o 0 dug along ! edge ( a simil> b     
small] dike4 ,all ^! deposits are       
insignificant 9 size & ( no comm]cial   
value4 ,_h !y be5 important ?is great   
area might nev] h be5 set aside z a     
national p>k4  ,illu/ration3 ,,m\nt     

,,wilbur ,,& ,,! ,,p9nacle ,,wall       
,,view$ ,,f ,,_m ,,glaci] ,,hotel4 ,,!  
,,upp] ,,"p ,,( ,,appekunny ,,& ,,all   
,,( ,,! ,,gr9nell ,,& ,,siyeh ,,=mations
 ,,are ,,visible4 ,,! ,,sn[-,,fill$     
,,*ute ,,left ,,( ,,! ,,^w ,,gr9nell    
,,is ,,=m$ ,,by ,,! ,,same ,,dike ,,:i* 
,,passes ,,?r\gh ,,! ,,p9nacle ,,wall4  
7,,hileman ,,photo1 ,,c\rtesy ,,glaci]  
,,p>k ,,co47                            
,! ,/ory ,cont9ues   ,= ! succe$+ sev]al
 hundr$ million ye>s ! geologic hi/ory (
 ,glaci] ,national ,p>k is r obscure1 b 
additional ,belt s$im5ts app>5tly 7     
deposit$ be=e uplift ( ! area caus$ !   
sea to )draw4 ,foll[+ ?is ev5t _m feet (
 ! y\ng] ,belt s$im5ts 7 remov$ by      
erosion4 ,! sea probably return$ &      
receiv$ m s$im5ts dur+ mu* ( !          
,paleozoic ,era1 al?\gh no trace ( ^!   
rocks has be5 f\nd inside ! p>k         
b\nd>ies4                               
,,cretace\s ,,rocks4  ,n until !        
,cretace\s p]iod ( ,e>? hi/ory1 ab\t    
#ajj million ye>s ago1 did ! geologic   

record aga9 become cle>4 ,at t "t a     
great ?ickness ( mud & s& 0 deposit$ 9 !
 geosyncl9e bury+ deeply ! anci5t ,belt 
& o!r rocks :i* _h accumulat$ z s$im5t  
dur+ ! prec$+ sev]al hundr$ million     
ye>s4 ,life _h made trem5d\s advances 9 
?is int]val1 & ! abundance ( fossils 9  
,cretace\s rocks indicates t ! sea sw>m$
 ) %ell$ creatures dur+ t p]iod4        
,,! ,,lewis ,,ov]?ru/4  ,t[>d ! end (   
,cretace\s "t trem5d\s cru/al =ces1     
pr9cipally f ! we/1 7 direct$ aga9/ !   
geosyncl9e ) ! result t its rocks 7     
compress$ & uplift$1 conv]t+ ! site ( ! 
=m] sea into a m\nta9\s region4 ,simil> 
activity took place ?r\gh\t ! l5g? &    
bread? ( ! entire geosyncl9e1 :i*       
result$ 9 ! =mation ( ! ,rocky ,m\nta9  
sy/em /ret*+ betwe5 ,mexico & ,alaska4  
,a numb] ( m\nta9s 7 =m$ on o!r cont95ts
 dur+ ?is p]iod4 ,s widespread &        
trem5d\s 0 ! de=mation1 especially 9 !  
pres5t day ,rocky ,m\nta9 region1 t x is
 kn[n z ! ,rocky ,m\nta91 or ,l>amide   
7aft] ! ,l>amie ,range 9 ,wyom+71       

revolution4 ,m\nta9-build+ =ces cont9u$ 
= sev]al million ye>s 9 ! ,glaci] ,p>k  
area1 f9ally squeez+ ! rocks into a     
great fold 7anticl9e74 ,cont9u$ pressure
 f ! we/ ov]turn$ ! fold & put          
additional /ra9 on ! rock lay]s1        
ev5tually caus+ !m to break along a     
great l[-angle fault4 ,! we/]n limb ( ! 
fold1 n[ a great slice ( ! cru/1 0 driv5
 upw>d & ea/w>d ov] ! ea/]n limb        
ultimately rev]s+ ! ord] ( rock lay]s by
 plac+ old] on top ( y\ng] ones 7,figure
 #c74 ,^! y\ng] lay]s are ,cretace\s    
%ales & s&/ones und]ly+ ! pla9s         
imm$iately ea/ ( ! m\nta9s4 ,! m\nta9s  
!mselves h be5 c>v$ by /reams & glaci]s 
f ! ,belt =mations compris+ ! upp] block
 ( old] rock1 t slice ( ! cru/ :i* has  
be5 mov$ m ?an #ae miles t[>d ! ea/4 ,! 
surface ov] :i* x 0 pu%$ is ! ,lewis    
ov]?ru/4 ,at ! "t ?is great break       
occurr$ ! "p ( x n[ expos$ 9 ,glaci]    
,national ,p>k 0 deeply buri$4 ,x 0 long
 aft] t :5 removal by erosion ( ov]ly+  
,belt rocks1 possibly sev]al ?\s& feet (

 !m1 f9ally expos$ ! fault4  ,,figure   
#b4 ,,map ,,( ,,wat]ton-,,glaci]        
,,int]national ,,peace ,,p>k    ,,leg5d 
#a4 ,,trace ,,( ,,lewis ,,ov]?ru/       
#b4 ,,alluvial ,,fans     #c4 ,,range   
,,cre/s     #d4 ,,highways  ,movem5t    
along ?is fault 0 sl[--s sl[ t _h p be5 
pres5t at ! "t !y probably w\ld n h be5 
aw>e t any?+ ( an unusual nature 0      
occurr+4 ,occasionally along _m l>ge    
faults1 h[ev]1 !re is sudd5 movem5t (   
small magnitude1 usually n m ?an a few  
in*es1 b /rong en\gh to vibrate ! cru/4 
,^! vibrations are e>?quakes1 & _!      
frequ5t occurr5ce 9 ,cali=nia & else:]e 
along ! ,pacific coa/ indicates !       
pres5ce ( num]\s active faults4 ,_!     
occurr5ce also 9 ! nor!rn ,rockies1 z at
 ,hel5a1 ,montana 9 #aice & #aicf1      
atte/s to ! fact t "s ( ! faults "h are 
/ill active4  ,! ,lewis ov]?ru/ comes to
 ! surface at ! base ( ! ,altyn =mation 
along ! entire precipit\s ea/ front ( ! 
,lewis ,range & c be trac$ ne>ly #ajj   
miles nor?w>d into ,canada & = almo/ an 

equal di/ance s\? ( ! p>k4 ,! section   
ly+ )9 ! p>k is tilt$ v g5tly t[>d !    
s\?we/1 ! angle ( dip seldom exce$+ t5  
degrees4 ,9 "s places x is practically  
horizontal4 ,= ?is reason ! l[] c\rses (
 all ! l>ge/1 & "s ( ! small1 valleys on
 ! ea/ side ( ! ,lewis ,range h be5 cut 
entirely ?r\gh ! upp] block 7ov]?ru/7 ( 
,belt rocks d[n into ! weak ,cretace\s  
%ales und]nea?4 ,?is causes ! trace ( ! 
ov]?ru/ to be v s9u\s & also acc\nts = !
 deep ind5tations 9 ! m\nta9 front =m$  
by ,swiftcurr5t1 ,/4 ,m>y1 ,two ,m$ic9e1
 & o!r valleys4 ,! floors 9 ! l[] c\rses
 ( ^! valleys1 because !y lie bel[ !    
level ( ! ?ru/ surface1 are compos$ (   
,cretace\s %ales4 ,9 mo/ places ^! rocks
 are cov]$ by glacial mora9e1 b !y are  
expos$ along ! highway f ,babb into !   
,swiftcurr5t ,valley1 especially along !
 %ore ( ,%]burne ,res]voir & ne> !      
entrance /ation4 ,because ^! %ales      
readily dis9tegrate :5 expos$ to !      
atmosph]e !y give rise to slumps &      
l&slides :i*1 al?\gh ( small            

proportions1 cause a great deal ( damage
 to ! highway1 sections ( :i* mu/ be    
rebuilt annually4 ,at mo/ damag$ spots  
along ! r\te ! %ales appe> z a d>k mud  
or clay 9 ! roadcuts4 ,! bumpy          
topography ( ! :ole slope ly+ nor? ( !  
road has be5 =m$ by innum]able su* small
 l&slides4  ,a deep well locat$ ne>     
,cam]on ,falls 9 ,wat]ton ,t[nsite      
7,wat]ton ,lakes ,national ,p>k7 ab\t "o
 mile we/ ( ! edge ( ! m\nta9s passes   
?r\gh #a1ejj feet ( ,belt rocks & !n    
p5etrates ! ,lewis ov]?ru/ & !          
,cretace\s %ales b5ea?4  ,9 ! s\!rn "p (
 ,glaci] ,national ,p>k j nor? ( ,m>ias 
,pass1 ,debris ,creek has cut a hole or 
w9d[ 7kn[n z a f5/] by geologi/s7 ?r\gh 
! ov]?ru/ block 7,figure #b74 ,?us a    
small area ( ,cretace\s rock completely 
surr\nd$ by ! ,belt s]ies lies )9 !     
m\nta9s4 ,?is is ! only su* ,cretace\s  
outcrop 9 ! p>k1 b l ! well at ,wat]ton1
 x s]ves z a rem9d] t ! rocks ( ?is     
p]iod are ev]y:]e pres5t "u ! m\nta9s1 &
 _! surface con/itutes ! slid+ bo>d ov] 

:i* ! upp]1 m massive block ( ,belt     
rocks 0 pu%$4 ,& s we see t ! m\nta9s ( 
,glaci] ,national ,p>k1 unlike _m ( !   
_w's great ranges1 h no roots1 = !y re/ 
on a base ( greatly diff]5t & mu* less  
resi/ant mat]ial1 ! ,cretace\s %ales4   
,presumably ! ,lewis ov]?ru/ &          
,cretace\s rocks b5ea? x w\ld be        
p5etrat$ by a well drill$ any:]e )9 !   
m\nta9s1 al?\gh 9 ! ,liv+/one ,range !  
dep? ( su* a well w\ld be v great       
7,figure #c;,d74  ,,figure #c4 ,,hi/ory 
,,( ,,lewis ,,ov]?ru/    ,a ,,hypo!tical
 ,,section ,,ne> ,,! ,,close ,,(        
,,cretace\s ,,"t4   ,b ,,pressure ,,f   
,,we/ ,,creates ,,l>ge ,,fold ,,&       
,,ov]turns ,,x ,,t[>ds ,,ea/4     ,,!   
,,new ,,m\nta9s ,,are ,,cut ,,d[n ,,by  
,,erosion4   ,c ,,cont9u$ ,,pressure    
,,breaks ,,! ,,/rata ,,& ,,! ,,lewis    
,,ov]?ru/ ,,is           ,,=m$4 ,,dott$ 
,,l9e ,,%[s ,,approximate ,,pres5t      
,,outl9e ,,(           ,,surface   ,d   
,,section ,,across ,,! ,,p>k ,,%[+      
,,relation%ips ,,( ,,rock ,,=mations ,,&

           ,,! ,,lewis ,,ov]?ru/        
7,,v]tical ,,scale ,,greatly            
,,exagg]at$7  ,erosion 9 ! ea/]n "p ( ! 
ov]?ru/ block1 9 addition to produc+ its
 cr5ulat$ edge1 has left sev]al isolat$ 
remnants 7outli]s7 ea/ ( ! ma9 mass ( ! 
m\nta9s4 ,! be/ kn[n ( ^! is ,*ief      
,m\nta9 situat$ ne> ! nor!a/ corn] ( !  
p>k sev]al miles we/ ( ! ,*ief ,m\nta9  
,int]national ,highway4 ,x is a mass (  
,altyn lime/one ris+ v]tically on its   
ea/1 s\? & nor? sides = a di/ance (     
#a1ejj feet4 ,! ,lewis ov]?ru/ is well  
expos$ all ar\nd its base4 ,two small]  
p9nacles imm$iately to ! we/ are simil> 
outli]s1 &1 l ,*ief ,m\nta91 7 once "p (
 ! ma9 mass ( ! ,lewis ,range 7,figure  
#c;,d & cov] sket*74 ,divide ,peak1 at !
 we/ end ( ,hudson ,bay ,divide1 is     
ano!r outli]4 ,x1 too1 is compos$       
entirely ( ! ,altyn =mation4  ,al?\gh ! 
,lewis ov]?ru/ is expos$ 9 a great numb]
 ( places v few ( ^! are easily         
accessible1 & at only "o does a trail   
provide a close approa* to ! actual     

contact betwe5 ,belt & ,cretace\s rocks4
 ,! latt] site lies along ,roes ,creek  
only a few hundr$ y>ds f ,ea/ ,glaci]   
,campgr\nd4 ,be=e rea*+ ! fault at !    
base ( a high cliff ( ,altyn lime/one1 !
 trail crosses sev]al outcrops (        
,cretace\s s&/one replete ) fossil      
pelecypods 7clams7 & ga/ropods 7snails74
 ,! fault surface is cov]$ by loose rock
 :]e ! trail crosses x1 b on ! opposite 
side ( ! /ream a zone ( cru%$ ,altyn    
lime/one & ,cretace\s %ale is visible4  
,f ,u4 ,s4 ,highway ,no4 #b j ea/ (     
,m>ias ,pass an excell5t di/ant view ( !
 ?ru/ may be obta9$4 ,ab\t ?ree miles to
 ! nor? x appe>s z a ne>ly horizontal   
l9e high on ! side ( ,summit ,m\nta94   
,above x is a v]tical cliff 9 :i* :ite  
,altyn & r$ ,gr9nell are prom95t1 & bel[
 is a g5tl] slope compos$ ( gray-br[n   
,cretace\s %ale4  ,cretace\s rocks )    
relatively l[ resi/ance to ,e>? /resses1
 7 /rongly crumpl$ & fold$ dur+ ! p]iod 
( ov]?ru/+4 ,! fold$ zone ext5ds sev]al 
miles ea/w>d f ! m\nta9s 7,figure #c    

,d71 & may be se5 to good advantage     
along ,blackfeet ,highway on ! nor? side
 ( ,two ,m$ic9e ,ridge1 :]e a s]ies ( ?9
 %ales & s&/ones has be5 squeez$ into   
anticl9es & syncl9es4  ,x is because ( !
 ,lewis ov]?ru/ t !re are no significant
 foo?ills on ! ea/ side ( ! ,lewis      
,range4 ,! fault has br\ght into direct 
contact ! massive & resi/ant ,belt rocks
 :i* /& up z m\nta9s1 & ! relatively    
weak %ales ( ! pla9s :i* are c>v$ into  
subdu$ l&scape features by erosion4     
,illu/ration3 ,,lewis ,,ov]?ru/ ,,at    
,,base ,,( ,,mt4 ,,wynn ,,se5 ,,f       
,,highway ,,ea/ ,,( ,,_m ,,glaci]       
,,hotel4 ,,ov]?ru/ ,,lies ,,at ,,base   
,,( ,,cliff4 ,,cretace\s ,,rocks        
,,outcrop ,,on ,,g5tle ,,slope ,,bel[   
,,?ru/4                                 
7,,dyson ,,photo7  ,aft] ! ,lewis       
ov]?ru/ _h tak5 place1 & probably foll[+
 a p]iod ( erosion1 ! we/]n "p ( ! block
 broke along a v]tical fault & sank     
sev]al ?\s& feet4 ,= a %ort p]iod ( "t a
 lake1 9 :i* clay 0 deposit$1 cov]$ !   

floor ( ?is depress$ area4 ,! pres5t    
valley ( ! ,nor? ,=k ( ! ,fla!ad ,riv]  
lies on ?is d[nfault$ block 7,figure    
#c;,d71 & ! we/]n b\nd>y ( ! ,liv+/one  
,range m>ks ! trace ( ! fault4 ,because 
! fault is ( ! high-angle v>iety ! front
 ( ?is range is mu* /raight] ?an t ( !  
,lewis ,range :i* is =m$ by ! not*$     
ea/]n edge ( ! relatively ?9 ov]?ru/    
block4 ,! ,belton ,hills & ,apg>        
,m\nta9s ne> ! p>k's we/ entrance are   
isolat$ blocks sep>at$ f ! ,liv+/one    
,range by normal faults probably dat+ f 
! "t ! ,nor? ,=k ,valley subsid$4       
,! ,effect ( ! ,ice ,age   ,9 ,mioc5e & 
,plioc5e "t ! m\nta9s 7 deeply erod$ by 
/reams4 ,x 0 dur+ ?is "t t ,*ief        
,m\nta91 ,divide ,peak1 & two small]    
outli]s1 & ! f5/] along ,debris ,creek 7
 =m$4 ,all ( ! exi/+ m\nta9 valleys 7   
cut out ( ! ov]?ru/ block1 al?\gh n to z
 great a dep? z !y h today4 ,! "t       
requir$ = _! =mation am\nt$ to sev]al   
millions ( ye>s4 ,! result ( all ?is    
erosion 0 a l&scape v simil> to ! pres5t

 day ,blue ,ridge 9 ,virg9ia & ,nor?    
,c>ol9a1 ! type :i* geologi/s call      
mature4  ,ne> ! close ( ,plioc5e "t !   
climate cool$1 timb]l9e began to l[]1 & 
increas+ am\nts ( p]man5t sn[ accumulat$
 9 ! high] p>ts ( ! m\nta9s4 ,f9ally    
glaci]s =m$ f ! sn[ & began to move d[n 
! /ream-c>v$ valleys4 ,?is m>k$ ! adv5t 
( ,plei/oc5e "t 7,! ,glacial ,age7 ne>ly
 a million ye>s ago4 ,glaci]s ev5tually 
fill$ all valleys & cov]$ all ! p>k area
 except ! summits ( ! highe/ peaks4     
,glaci]s ext5d$ f valleys on ! ea/ side 
( ! ,lewis ,range f> out onto ! pla9s1 &
 f ! ,liv+/one ,range & ! we/ side ( !  
,lewis ,range !y mov$ into ! wide       
,fla!ad ,valley4 ,! =e/s disappe>$ & x  
is probable t n a s+le tree rema9$ 9 !  
area :i* is n[ ! p>k4 ,available evid5ce
 indicates t climatic fluctuations dur+ 
,plei/oc5e "t caus$ ! glaci]s to        
disappe> = a consid]able p]iod ( "t1 or 
at lea/ to %r9k to insignificant size & 
!n to return4 ,at ! end ( ,plei/oc5e "t 
!y began to %r9k & ab\t #i1jjj ye>s ago1

 dur+ :at is g5]ally reg>d$ z           
po/-,plei/oc5e "t1 disappe>$ aga94  ,!  
l>ge ,plei/oc5e glaci]s greatly alt]$ ! 
pre-exi/+ l&scape ( ! p>k by g\g+ out   
valleys to mu* great] dep?1 & mak+ _!   
sides & heads mu* /eep] ?an ! /reams _h 
be5 able to cut !m4 ,mo/ ( ! lakes1     
v]tical cliffs1 %>p peaks1 & wat]falls  
:i* con/itute mu* ( ! p>k's magnific5t  
sc5]y 7 creat$ z a result ( int5sive    
glaci] action4#d                        
,! ,la/ ,*apt]   ,al?\gh ev5ts ( ! la/  
#i1jjj or s ye>s didn't create ! l>ge   
spectacul> features ( ! l&scape1 ?is    
p]iod is none!less int]e/+ because x    
witness$ ! bir? ( all exi/+ p>k glaci]s 
& ! return ( ! trees compos+ !          
pres5t-day =e/s4 ,z soon z ! glaci]s    
began to %r9k trees und\bt$ly />t$ to   
reclo! ! newly expos$ surfaces4 ,new    
v>ieties came f areas :i* _h n be5      
glaciat$4 ,f ! ,pacific coa/ came gr&   
fir1 ,d\glas fir1 l>*1 hemlock1 :ite p9e
 & o!rs4 ,f ! ea/ came ano!r gr\p       
includ+ asp51 pap] bir*1 haw?orn &      

maple4 ,! native trees driv5 out by !   
ice also return$ to aga9 become         
important elem5ts ( ! flora4 ,^! are    
,engelmann spruce1 alp9e fir1 &         
lodgepole p9e4 ,a few species1 among :i*
 are ! alp9e will[s1 driv5 s\?w>d f ! f>
 nor? dur+ ! ,plei/oc5e p]iod /ill p]si/
 at high altitudes b !y are always ready
 to move d[n into ! valleys if ! climate
 %\ld aga9 become cool4 ,( c\rse1       
cont9u$ w>m+ w\ld cause !m to disappe>4 
,aft] ! l>ge ,plei/oc5e /reams ( ice    
disappe>$ !re foll[$ a p]iod ( ab\t     
#e1jjj ye>s dur+ :i* ! climate 0 some:at
 w>m] & dri] ?an at pres5t1 conditions  
"u :i* ev5 v small glaci]s c\ld n h     
surviv$4 ,!n ab\t #d1jjj ye>s ago !     
adv5t ( ! cool] climate br\ght ab\t !   
orig9 ( ! pres5t glaci]s4 ,dur+ ! p]iod 
( _! exi/5ce !y h fluctuat$ 9 size1     
probably atta9+ maximum dim5sions ar\nd 
! middle ( ! la/ c5tury4 ,s9ce !n !y h  
be5 /eadily %r9k+1 a sure indication t !
 climate is becom+ mild]1 z x has s _m  
times 9 ! pa/4  ,illu/ration3 ,,m\nt    

,,jackson1 ,,visible ,,f                
,,go+-,,to-,,!-,,sun ,,highway1 ,,is    
,,compos$ ,,( ,,/eeply ,,tilt$ ,,/rata  
,,( ,,! ,,siyeh ,,=mation4 ,,jackson    
,,glaci] ,,to ,,! ,,left ,,( ,,!        
,,m\nta9 ,,lies ,,on ,,! ,,surfaces ,,( 
,,sev]al ,,( ,,^! ,,/rata4              
7,,dyson ,,photo7  ,surr\nd+ all ^!     
small glaci]s are rec5t mora9es compos$ 
( rock debris erod$ f ! bas9s 9 :i*     
glaci]s lie4 ,^! mora9es ?us repres5t ! 
am\nt ( mat]ial remov$1 & !n deposit$1  
)9 ! la/ #d1jjj ye>s4 ,!y are p>ticul>ly
 /rik+ at ,gr9nell & ,sp]ry ,glaci]s &  
at ! site ( ! =m] ,clem5ts ,glaci] ne>  
,logan ,pass4  ,illu/ration3 ,,mora9e   
,,ne> ,,gr9nell ,,glaci] ,,is #abj      
,,feet ,,high4                          
7,,dyson ,,photo7  ,foll[+ disappe>ance 
( ! l>ge ,plei/oc5e glaci]s /reams      
return$ to ! valleys & began to cut new 
valleys )9 ! old4 ,because              
po/-,plei/oc5e "t has be5 ( su* %ort    
duration ^! new valleys are small y\?ful
 gorges4 ,int]e/+ examples are ,sunrift 

,gorge1 :]e ,b>+ ,creek has cut a n>r[  
*annel into ! upp] "p ( ! ,appekunny    
=mation2 & ! gorge at ,hidd5 ,falls on  
,hidd5 ,creek 9 ! ,gr9nell ,valley4     
,sunrift ,gorge lies only a few feet    
nor? ( ,go+-to-!-,sun ,highway at ,b>+  
,creek bridge1 & ,hidd5 ,gorge is a /op 
on ! guid$ trip :i* ,rang]-,naturali/s  
conduct f ,_m ,glaci] ,hotel to ,gr9nell
 ,lake4 ,bo? ( ^! *annels h v smoo?1    
/raight sides because !y h be5 erod$    
along v]tical fractures kn[n z jo9ts4 ,!
 latt] are common ?r\gh\t ! m\nta9s &   
are responsible = ! smoo? surfaces on "s
 ( ! highe/ cliffs4 ,! gorge ( ,avalan*e
 ,creek ne> ,avalan*e ,campgr\nd is     
ano!r example ( po/-glacial /ream       
erosion1 only "h ! :irl+ action ( s& &  
gravel-lad5 wat] has c>v$ out a numb] ( 
cyl9drical po?oles 9 ! /ream c\rse4 ,"s 
( !m1 ?\gh only #f to #aj feet across1  
are #bj or m feet deep4  ,s9ce we "k t !
 /reams did n beg9 to cut ^! gorges     
until ! l>ge ,plei/oc5e glaci]s _h      
disappe>$ f ^? sites1 approximately     

#aj1jjj ye>s h be5 requir$ = _! =mation4
 ,?us ! av]age maximum rate ( d[n-cutt+ 
has be5 ( ! magnitude ( #j4jjb to #j4jjc
 in* p] ye>4 ,) ^! figures z a f\ndation
 x is n s difficult to compreh5d t ! mu*
 l>g] valleys ( ! p>k c\ld n h be5 erod$
 9 less ?an sev]al millions ( ye>s4     
,ano!r common1 ?\gh seldom notic$1      
po/-glacial feature ( ! p>k is !        
alluvial fan4 ,^! are fan-%ap$          
accumulations ( gravel deposit$ by      
swift1 tribut>y /reams :]e !y ent] a ma9
 valley4 ,"s ( !m h gr[n s l>ge z to dam
 ! /ream 9 ! major valley & cause a lake
 7,figure #b74 ,/4 ,m>y1 ,l[] ,/4 ,m>y1 
,l[] ,two ,m$ic9e1 & ,wat]ton ,lakes are
 held 9 by su* dams4 ,! alluvial fan (  
,divide ,creek :i* holds 9 ,/4 ,m>y     
,lake c easily be di/+ui%$ f            
,go+-to-!-,sun ,highway on ! nor? side (
 ! lake ne> its outlet4 ,! ,/4 ,m>y     
,entrance ,/ation is locat$ on ?is fan4 
,! l[] lake is damm$ by a l>ge fan built
 into ! ,/4 ,m>y ,valley by ,swiftcurr5t
 ,creek4 ,! /raight section ( highway   

betwe5 ! t[n ( ,babb & ! ,/4 ,m>y ,riv] 
bridge lies on ! l[] "p ( ?is fan4      
,inasmu* z ! ,plei/oc5e glaci]s         
und\bt$ly remov$ any su* fans made      
previ\sly1 ^? :i* are pres5t today mu/ h
 be5 con/ruct$ s9ce disappe>ance ( !    
ice1 & are !n n m ?an #ab1jjj ye>s old4 
,mo/ ( !m are some:at old]1 possibly by 
z mu* z two or ?ree ?\s& ye>s1 ?an !    
gorges m5tion$ above1 because ! latt]   
are locat$ ne>] ! s\rce ( ! glaci]s1 &  
_! sites 7 ?us /ill cov]$ by ice aft] ! 
fans _h already begun to =m4 ,aft] !    
,plei/oc5e glaci]s began _! f9al retreat
 sev]al ?\s& ye>s elaps$ be=e !y        
disappe>$ f ! m\nta9s4  ,illu/ration3   
,,front ,,( ,,lewis ,,range1 ,,nor?     
,,side ,,( ,,swiftcurr5t ,,valley4 ,,!  
,,lewis ,,ov]?ru/ ,,lies ,,at ,,! ,,base
 ,,( ,,! ,,cliff4 ,,?ree ,,l>ge ,,talus 
,,cones ,,are ,,visible ,,bel[ ,,mt4    
,,altyn ,,on ,,! ,,left4                
7,,dyson ,,photo7  ,"o ( ! mo/          
conspicu\s ( all po/-glacial features is
 ! talus cone1 an accumulation ( angul> 

rock fragm5ts :i* fall f cliffs4 ,x is  
only at ! base ( a crevice or *imney t  
?is mat]ial takes ! app>5t =m ( a di/9ct
 cone4 ,else:]e x is ref]r$ to z a talus
 slope or simply z talus1 or1 9 !       
p>lance ( "s m\nta9e]s1 z scree4 ,al?\gh
 sev]al ?\s& ye>s h be5 requir$ = _!    
=mation mo/ talus accumulations 9 ! p>k 
are /ill actively gr[+1 especially 9    
spr+ & e>ly summ] :5 rocks are pri$     
loose by ! alt]nate freez+ & ?aw+ (     
moi/ure )9 fractures4 ,! artill]y-l     
crack made :5 a fall+ rock cra%es to !  
base ( a high cliff is a famili> s\nd to
 anyone :o has sp5t mu* "t 9 ! m\nta9s4 
,! ,future   ,we "k t ! processes (     
erosion & wea!r+ w cont9ue1 t alluvial  
fans & talus cones w gr[ l>g]1 & gorges 
w be erod$ deep]1 & z a result ! m\nta9s
 w be cut d[n to l[] elevations4 ,b1 z  
we h se51 ?is ev5t w require mu* "t4 ,if
 ! pres5t climate cont9ues = a few m    
ye>s our rema9+ glaci]s w disappe>1 b   
!re is no?+ 9 geologic hi/ory :i* says  
!y won't return aga91 possibly ev5 to ! 

size ( _! heyday 9 ! ,plei/oc5e4 ,& if  
hi/ory repeats itself1 & all pa/        
geologic hi/ory has be5 a repetition1 !n
 ! m\nta9s w ev5tually be worn d[n to an
 unev5tful pla9 & ! sea w invade ! l&   
aga94  ,b c]ta9 bre$s ( man are ! only  
despoil]s ( m\nta9s t we ne$ fe>1 s if !
 good citiz5s ( our l& keep ! human     
invad] & 8 dams & e>?-mov+ equipm5t out 
( our national p>ks ^! gr& m\nta9s w    
endure = _m ?\s&s1 yes1 ev5 millions (  
ye>s4                                   
,footnotes   #a;,dr4 ,dyson work$ z a   
rang]-naturali/ 9 ,glaci] ,national ,p>k
 =     eight summ]s />t+ 9 #aice4       
#b;,argillite is ! t]m us$ by geologi/s 
= a rock1 orig9ally a     %ale1 :i* has 
be5 recry/alliz$ or made h>d] by great] 
pressure4 ,9 ext]nal appe>ance x looks l
 %ale4  #c;,a dike is l a sill 9 all    
respects except t x cuts across         
adjac5t lay]s in/ead ( p>allel+ !m4     
#d;,= a complete discussion ( glaci]s & 
_! effects see ,special     ,bullet9    
,no4 #b 7,glaci]s & ,glaciation 9       

,glaci] ,national ,p>k7 (     ! ,glaci] 
,natural ,hi/ory ,association4          
,,pr9t$ ,,9 ,u4 ,s4 ,a4                 
,,by                   ,,glaci]         
,,natural ,,hi/ory ,,association        
,,9 ,,coop]ation ,,)                    
,,national ,,p>k ,,s]vice    ,,dep>tm5t 
,,( ,,int]ior                           
#aiec                   ,o',,neil       
,,pr9t]s--,,kalispell1 ,,montana        
,pr9cipal ,aims ( ! ,,glaci] ,,natural  
,,hi/ory ,,association1 ,inc4           
,glaci] ,national ,p>k                  
,we/ ,glaci]1 ,montana  ,organiz$ = !   
purpose ( coop]at+ ) ! ,national ,p>k   
,s]vice by assi/+ ! ,naturali/ ,dep>tm5t
 ( ,glaci] ,national ,p>k 9 ! developm5t
 ( a broad public und]/&+ ( ! geology1  
plant & animal life1 hi/ory1 ,indians & 
relat$ subjects be>+ on ! p>k region4 ,x
 aids 9 ! developm5t ( ! ,glaci]        
,national ,p>k museum libr>y1 museums & 
wayside exhibits2 (f]s books on natural 
hi/ory p]ta9+ to ?is area = sale to !   
public2 assi/s 9 ! acquisition (        

non-f$]ally own$ l&s )9 ! p>k 9 behalf (
 ! ,unit$ ,/ates gov]nm5t2 & coop]ates )
 gov]nm5t projects 9 ! completion &     
developm5t ( ,glaci] ,national ,p>k z   
ne$$4  ,rev5ue d]iv$ f ! activities ( ! 
,glaci] ,natural ,hi/ory ,association is
 devot$ entirely to ! purposes outl9$4  
,any p]son int]e/$ 9 ! fur!rance ( ^!   
purposes may become a memb] ^u paym5t ( 
! annual fee ( "o doll>4 ,gifts &       
donations are accept$ = l& acquisition  
or g5]al use4    ,bullet9 ,no4          
#a--,motori/s ,guide to ! ,go+-to-!-,sun
 ,highway1           #aidg--,price #be  
,c5ts4   ,bullet9 ,no4 #b--;,glaci]s &  
,glaciation 9 ,glaci] ,national ,p>k1   
#aidh--,price #be ,c5ts4   ,bullet9 ,no4
 #c--;,geologic ,/ory ( ,glaci]         
,national ,p>k1 #aidi--,price           
#be ,c5ts4   ,bullet9 ,no4 #d--,trees & 
,=e/s ( ,glaci] ,national ,p>k1         
#aiej--,price #ej ,c5ts4   ,bullet9 ,no4
 #e--aja ,wildfl[]s ( ,glaci] ,national 
,p>k1 #aieb--,price           #ej ,c5ts4
                                        

,transcrib]'s ,notes   --,copyright     
notice provid$ z 9 ! orig9al--?is e-text
 is public   doma9 9 ! c\ntry (         
publication4  --,sil5tly correct$       
palpable typos1 leav+ non-/&>d spell+s &
   dialect un*ang$4  --,only 9 ! text   
v]sions1 delimit$ italiciz$ text 7or    
non-italiciz$ text )9 poetry7 9         
und]scores 7! ,,html v]sion   reproduces
 ! font =m ( ! pr9t$ book47