,,geologic ,,sett+ ,,( ,,!              
,,john ,,day ,,c\ntry1                  
,,grant ,,c\nty1 ,,oregon               
,,unit$ ,,/ates ,,dep>tm5t ,,( ,,!      
,,int]ior_/ ,,geological ,,survey       
,illu/ration3 ,! t[n ( ,john ,day1 !    
,john ,day ,riv] valley1 & !  ,/rawb]ry 
,range1 look+ s\? & s\!a/4 ,! tail+s    
piles left  by gold dr$ges h be5 levell$
 = build+ sites s9ce !  photograph 0    
tak5 9 #aidf4    ,"o ( ! ,pacific       
,nor?we/'s mo/ notable outdoor          
recreation areas1  ! 8,john ,day        
,c\ntry0 9 nor!a/]n ,oregon1 is nam$    
aft] a native  ,virg9ian :o 0 a memb] ( 
! ,a/or exp$ition to ! m\? ( !          
,columbia ,riv] 9 #ahab4    ,!re is     
little factual in=mation ab\t ,john ,day
 except t he 0  born 9 ,culpep] ,c\nty1 
,va4 ab\t #aggj4 ,x is kn[n also t 9    
#ahaj  ?is tall pione] 8) an ela/ic /ep 
z if he trod on spr+s0 jo9$  ,john      
,jacob ,a/or's ov]l& exp$ition "u       
,wilson ,price ,hunt to  e/abli% a va/  
fur-ga!r+ network 9 ! we/]n /ates bas$  

on a  major trad+ po/ at ! m\? ( !      
,columbia ,riv]4    ,! exp$ition arriv$ 
9 ! vic9ity ( ! ,gr& ,tetons1 9 :at is  
n[ ,wyom+1 9 ,septemb] #ahaa1 & ) !     
onset ( w9t] met  disa/] along ! ,snake 
,riv]4 ,:5 !y ran out ( food ne> !      
pres5t site ( ,tw9 ,falls1 ,idaho1 ,hunt
 divid$ ! exp$ition into f\r  p>ties to 
seek food & a feasible r\te ?r\gh !     
canyons4 ,z  describ$ 9 ,wa%+ton ,irv+'s
 ,a/oria1 ! p>ty t includ$ ,john  ,day  
became widely sep>at$ f ! o!rs2 exp]i5c$
 t]rible  h>d%ips :ile w9t]+ ) ,indians 
ne> ,hunt+ton2 & 0  ev5tually r$uc$ to j
 ,john ,day & ,ramsey ,crooks4 ,by      
mid-,april (  ! foll[+ ye>1 ,day &      
,crooks rea*$ ! junction ( ! ,columbia  
& ,mah-hah ,riv]s1 :]e a b& ( ,indians  
took ev]y?+ !y _h1  includ+ _! clo!s4   
,because ( ?is incid5t1 ! ,mah-hah ,riv]
 0  r5am$ ! ,john ,day4 ,return+ up !   
,columbia to seek help f  fri5dly       
,indians1 !y 7 rescu$ by a p>ty (       
trapp]s 9 canoes1  & f9ally rea*$       
,a/oria on ! #aa? ( ,may #ahab4         

,al?\gh ! fir/ discov]y ( gold 9 ,oregon
 report$ly 0 made 9  #ahde on "o ( !    
upp] bran*es ( ! ,john ,day ,riv] by a  
memb] (  an immigrant tra91 ! settlem5t 
( ! ,john ,day ,c\ntry really began  9  
#ahfb1 :5 gold 0 discov]$ 9 ,canyon     
,creek j above ,canyon  ,city4 ,s9ce !n1
 possibly #cj1jjj1jjj wor? ( gold has   
be5 m9$1  mo/ly f gravels 9 & along     
,canyon ,creek & along a #aj-mile  /ret*
 ( ! ,john ,day ,riv]4 ,lumb]+ & ran*+  
are n[ !  pr9cipal indu/ries ( ! region4
    ,! gr[? ( t\rism 9 ,oregon & ,grant 
,c\nty & ! accompany+  increase ( int]e/
 9 geology h /imulat$ ! prep>ation ( ?is
  leaflet4 ,! ,grant ,c\nty ,plann+     
,commission & ,/ate ,dep>tm5t (         
,geology & ,m9]al ,indu/ries h coop]at$ 
mo/ cordially 9 !  program to bett] in=m
 int]e/$ visitors ab\t ! geology ( !    
c\ntry !y are see+4                     
,,geologic ,,hi/ory      ,! ,john ,day  
,c\ntry ( today cov]s an area (         
#d1jjj-e1jjj squ>e miles  9 ! s\?we/]n  
"p ( ! ,blue ,m\nta9 region ( ,oregon1 &

 is  9 ! bord]l& betwe5 two major       
geologic prov9ces4 ,"o1 to !  nor?1 is !
 ,columbia ,plateau :i* consi/s ( flat  
or g5tly tilt$  fl[s ( basalt cov]+ ab\t
 #ajj1jjj squ>e miles4 ,! o!r1 to !     
s\?1 is ! ,bas9 & ,range ,prov9ce :i*   
ext5ds into ,mexico1 & is  *>act]iz$ by 
a wide v>iety ( complexly fold$ & fault$
 rocks4  ,! ,/rawb]ry-,aldri* ,m\nta9   
,range1 ris+ f #g1jjj to #i1jjj feet  9 
altitude along ! s\? side ( ! ,john ,day
 ,riv] valley 7see  ,figure #ac on page 
#ba71 is "p ( a #aej-mile long1         
ea/-tr5d+  m\nta9 *a9 t locally sep>ates
 ! two prov9ces4    ,_m features t      
record ev5ts 9 ! geologic hi/ory (      
nor!a/]n  ,oregon may be se5 9 ! rocks  
along ! pav$ highways )9 ! ,john  ,day  
,c\ntry4 ,a road log describ+ "s ( ^!   
features is includ$ z  a "p ( ?is       
booklet4 ,! locations ( pr9cipal po9ts (
 int]e/1  key$ 9 ! road log to /ate     
highway mile po/s1 are %[n on ! map     
accompany+ ! road log4    ,! kn[n "p ( !
 geologic hi/ory ( ! ,john ,day ,c\ntry 

began  ) lava fl[s & deposition (       
volcanic a%1 s&/one1 %ale1 &  small     
l5ses ( lime/one 9 a late ,paleozoic sea
 m ?an #bej million  ye>s ago4 ,sometime
 betwe5 #bjj & #bej million ye>s ago1   
p]idotite  & gabbro 7d>k1 magnesium-ri* 
v>ieties ( igne\s rock7 rose f  great   
dep?s &1 z molt5 mat]ial 7magma71 invad$
 ! preexi/+  m>9e deposits4 ,^! igne\s  
rocks n[ =m ! core ( ,canyon  ,m\nta9 & 
c be se5 along ! precipit\s walls (     
,canyon ,creek4  ,masses ( *romium ore  
7*romite7 7 c>ri$ upw>d ) ! molt5       
mat]ial4 ,aft] erosion _h expos$ !      
p]idotite & gabbro1 ! area  0 subm]g$   
aga9 &1 dur+ ,late ,triassic & ,e>ly    
,jurassic "t  7ab\t #ahj million ye>s   
ago71 ! ,aldri* ,m\nta9 area 0 "p ( a   
seaway into :i* lavas fl[$4 ,?\s&s (    
feet ( volcanic a% f  active volcanoes  
accumulat$ 9 ! sea1 & betwe5 eruptions  
great  ?icknesses ( mud/one & %ale 7    
deposit$4 ,! cuts along ,u4 ,s4         
,highway #cie betwe5 ,canyon ,creek &   
,be> ,valley are 9 ^! rocks4  ,dur+ "p (

 ?is volcanic activity1 ,canyon ,m\nta9 
/ood z a high  l&mass1 b f9ally x too 0 
deeply buri$4 ,aga9 ! region em]g$  &   
probably 0 dry l& dur+ ! la/ half (     
,jurassic "t 7#ace to  #aej million ye>s
 ago74    ,9 ,e>ly ,cretace\s "t1 molt5 
mat]ial 0 intrud$ to =m !  granitic     
rocks 9 ! ,aldri* ,m\nta9s & ne> ,dixie 
,butte1 nor!a/  ( ,prairie ,city4 ,!    
gold ve9s 9 ,canyon ,m\nta9 & 9 mo/ ( ! 
,blue ,m\nta9 region probably 7 =m$ at t
 "t by solutions f  ! granitic magma4   
,scatt]$ pat*es ( fossilif]\s s&/one &  
conglom]ate l t 9 ,goose ,rock 7see     
,figure #e on page #aj7 %[ t  ! sea     
encroa*$ on ! ,blue ,m\nta9 region      
briefly dur+ ,cretace\s  "t aft] erosion
 _h expos$ ! granites4 ,! %orel9e 0 n f>
  ea/ ( ! ,john ,day area4    ,= ! pa/  
#fj million ye>s1 ea/]n ,oregon has be5 
a l& (  volcanoes1 m\nta9 build+1 &     
erosion4 ,aft] ! retreat ( !  ,cretace\s
 sea & an undef9$ p]iod ( erosion1      
volcanic eruptions  f widely scatt]$    
c5t]s dur+ ! ,eoc5e ,epo* buri$ ! region

  "u sev]al ?\s& feet ( volcanic rocks  
:i* n[ =m ! ,cl>no  ,=mation2 locally ^!
 rocks consi/ mo/ly ( &esitic lava fl[s 
& co>se mud-fl[ breccias4 ,! ,cl>no     
,=mation 0 ext5sively  fold$ & fault$ & 
deeply erod$ be=e ano!r s]ies (         
volcanoes  9 & some:at ea/ ( ! ,cascade 
,m\nta9s erupt$ rhyolitic a% t  0 bl[n  
ea/w>d & deposit$ z ! ,john ,day        
,=mation dur+ !  ,oligoc5e ,epo*4 ,!    
,john ,day ,=mation appe>s to h be5     
re/rict$  to a l[l& area :i* geologi/s  
today call ! ,john ,day bas91  locat$   
betwe5 ! pres5t site ( ! ,cascade       
,m\nta9s & !  ance/ral ,blue ,m\nta9s4  
,! ,cl>no & ,john ,day b$s 9 ?is bas9   
are  _w fam\s1 hav+ yield$ ?\s&s (      
bones1 leaves1 & pieces (  petrifi$ wood
 t 7 buri$ & pres]v$ by ! volcanic a% 9 
a  mann] simil> to ! burial ( ,pompeii  
by ! eruption ( ,mt4 ,vesuvius  9 #gi   
,a4 ,d4 ,ar*aic l>ge mammals su* z !    
titano!res1 & small  ance/ors ( mod]n   
mammals su* z ! #d-to$ =e/ horse        
,eohippus1  :i* 0 ! size ( a fox t]ri]1 

roam$ subtropical =e/s dur+  ! ,eoc5e   
,epo*4 ,_m important l9ks 9 !           
evolution>y *a9 (  mammals h be5 f\nd 9 
! ,john ,day fossil b$s2 = example1 !   
#c-to$ horse ,mesohippus1 :i* 0 a =e/   
dwell] ! size ( a  %eep1 _h tee? = br[s+
 in/ead ( graz+4      ,! mod]n day      
l&scape began to take =m 9 ,middle      
,mioc5e "t1 :5  ! basalt fl[s :i* cov]  
mo/ ( ! area & are expos$ 9 !  walls (  
,picture ,gorge 7h5ce _! "n1 ,picture   
,gorge ,basalt7 buri$  ! l&scape =m$ on 
! ,john ,day ,=mation & old] rocks4 ,!  
basalt erupt$ f long cracks or fissures 
9 ! ,e>?'s cru/ &  =m$ floods ( v fluid 
lava :i* fl[$ = di/ances up to "o       
hundr$ miles4 ,^! basalts are recogniz$ 
by geologi/s to be ( a  di/9ct type1    
commonly call$ plateau or flood basalt4 
,basalt1 froz5  9 ! fissures1 =ms dikes 
t commonly wea!r out above !  adjo9+    
s(t] rocks1 z %[n 9 ! picture ( ,kimb]ly
 ,dike on page  #af4    ,:ile ! ,picture
 ,gorge ,basalt 0 flood+ mo/ ( ! ,john  
,day bas91  sev]al volcanoes 9 ! vic9ity

 ( ,/rawb]ry ,m\nta9 erupt$  &esitic to 
rhyolitic lava & a%1 & built up cones   
simil> to ,mt4  ,hood & ! o!r high peaks
 ( ! ,oregon ,cascades4 ,geologi/s h    
nam$ ! remnants ( ^! cones ! ,/rawb]ry  
,volcanics4 ,because  ^! volcanoes rose 
sev]al ?\s& feet above ! top ( !        
,picture  ,gorge ,basalt1 a% & erosional
 debris f !m wa%$ out ov] !  basalt2 ^! 
mat]ials con/itute ! ,mascall ,=mation4 
,al?\gh !  m\nta9s 7 timb]$1 ! l[l&s    
probably 7 op5 & grassy4  ,bones & tee? 
( a pony-size ?ree-to$ horse1           
,m]y*ippus1 h  be5 dug f ! ,mascall     
,=mation4 ,:5 ! eruptions ceas$ 9 ,e>ly 
,plioc5e "t 7ab\t #aj million ye>s ago71
 ! entire ,blue ,m\nta9  region probably
 resembl$ ! ea/]n "p ( ! ,cascade       
,m\nta9s 9  ,oregon today1 p>ticul>ly ! 
area betwe5 ,mt4 ,hood & ,crat] ,lake4  
,! pres5t ,/rawb]ry-,aldri* ,m\nta9     
range & ! ridges & valleys  nor? ( x 7  
=m$ :5 ! ,e>?'s cru/ buckl$ & broke "u  
/rong compressive =ces f ! nor? & s\?4  
,p>tly by b5d+ or  fold+1 & p>tly by    

break+ along ! ,john ,day & o!r faults1 
!  ,/rawb]ry-,aldri* ,m\nta9s 7         
gradually rais$ a mile & a half to  two 
miles above ! valley to ! nor?4 ,! floor
 ( ! ma9 ,john ,day  ,riv] valley 0     
fill$ ) gravels erod$ f ! ris+ m\nta9s  
&1 z ! fold+ & fault+ & erosion sl[$1 an
 ext5sive1  broad1 g5tly slop+ surface 0
 =m$ on top ( ! valley fill4  ,:ile ^!  
gravels 7call$ ! ,rattlesnake ,=mation7 
7  accumulat+1 h[ev]1 a great volcanic  
eruption spread an a% fl[ m  ?an #ajj   
feet ?ick ov] ! entire l5g? ( ! ,john   
,day valley floor2  remnants ( ?is fl[  
=m prom95t rim-rocks betwe5 ! t[n (     
,john  ,day & ,picture ,gorge4 ,bones ( 
,hipp>ion1 a horse ! size ( a pony  :i* 
_h feet & tee? l mod]n horses1 h be5    
f\nd 9 !  gravels "u ! a% fl[4          
,,! ,,pres5t ,,l&scape      ,diff]5ces 9
 ! rates ( erosion ( v>i\s rocks 7 z    
important  z fold+ & fault+ 9 =m+ !     
topographic features 9 ! ,john  ,day    
,c\ntry4 ,! *ief ag5ts ( erosion are    
*emical wea!r+  processes t ev5tually   

break d[n or decompose all rocks1 &     
runn+  wat] :i* c>ries away ! wea!r$ or 
p>tly wea!r$ & brok5  mat]ial4 ,picture 
,gorge is n>r[ because ! basalts 9 !    
walls are  v resi/ant to wea!r+ & break 
along v]tical jo9ts into l>ge  blocks t 
d n move easily4 ,9 contra/1 ! ,john    
,day ,riv] has cut  a broad1 flat-floor$
 valley 9 ! ,mascall ,=mation at ! s\?  
end  ( ,picture ,gorge because ! a%y b$s
 wea!r to f9e clay :i* is  easily wa%$  
away4    ,l&slides h m>k$ ! face ( !    
,john ,day ,c\ntry4 ,l>ge rock  masses  
commonly slide :]e /eep cliffs =m 9 s(t 
rocks t are  capp$ by h>d resi/ant      
rocks4 ,:5 ! cliff face becomes too high
 &  /eep1 ! s(t b$s give way & l>ge     
blocks or masses slide d[nw>d1  usually 
tilt+ backw>d z !y move1 z %[n 9 !      
diagram (  ,ca!dral ,rock on page #ae4  
,ca!dral ,rock & two small l&slides nor?
  ( ! riv]1 ab\t two miles ea/ ( ,john  
,day1 %[ ?is classic =m4  ,_m l&slides1 
h[ev]1 are j jumbl$1 hummocky masses (  
slump$  mat]ial4 ,l>ge-scale l&slid+ 9 !

 ,john ,day ,=mation "u !  ,picture     
,gorge ,basalt is colorfully display$   
along ! riv] = #h miles  nor? ( ,picture
 ,gorge4 ,"s l&slides occur sudd5ly1 b  
_m move  =w>d only z fa/ z ! toe or l[] 
end is erod$ away1 z at  ,sunk5 ,m\nta94
    ,glaci]s h sculptur$ ! pr9cipal     
valleys t lie above an  altitude ( ab\t 
#e1jjj feet4 ,mov+ ice1 hundr$s ( feet  
?ick1  pluck$ out semi-circul>          
amphi!at]s call$ cirques at ! heads (  !
 valleys4 ,! #b1jjj-;foot cliffs above  
,little ,/rawb]ry ,lake 7  =m$ ?is way4 
,rocks held 9 ! ice1 l ! tee? ( a giant 
rasp1  gr\nd (f irregul>ities & wid5$ ! 
valley bottoms to a broad ,u  %ape z !  
glaci]s mov$ d[n ! valleys4 ,!          
effectiv5ess ( ice  sc\r c be se5 by    
comp>+ glaciat$ ,/rawb]ry ,creek above  
,/rawb]ry ,lake 7z %[n 9 figure #ae on  
page #bb7 ) unglaciat$  ,picture ,gorge 
or ) ,canyon ,creek j above ,canyon     
,city4                                  
,,road ,,log ,,( ,,! ,,john ,,day       
8,,loop0      ,,note3 ,mileages at      

lett]$ /ops on ! map 7,fig4 #a7 ref] to 
ne>by  mile po/s4 ,^! are n 9 num]ical  
ord] because ! r\te cov]s  p>ts ( f\r   
diff]5t numb]$ highways4 ,by tak+ ! t\r 
clockwise1  ! travel] w be at high]     
altitudes lat] 9 ! day4                 
,a4 #aee4d    ,holliday ,re/ ,area4 ,!  
ma9 ,john ,day fault1 :i* "h is buri$   
"u riv] gravel1 is believ$ to be j s\? (
 ! re/ area4 ,a  p>allel /ep fault      
7,fig4 #b7 cuts f left to "r across !   
s\!rn  slope ( ,mt4 ,v]non ,butte ab\t  
:]e ! junip] trees ?9 out4 ,fl[s  (     
,picture ,gorge ,basalt 9 ! upp] "p ( ! 
butte slope d[n to  valley level on y\r 
left4 ,rocks 9 ! =egr\nd & to ! "r are  
rudely b$d$ volcanic breccias ( ! ,cl>no
 ,=mation4 ,! ,cl>no  ,=mation has be5  
rais$ z mu* z #bej feet by movem5t along
 !  fault to position x aga9/ ! basalt z
 indicat$ 9 ! diagram4 ,!  fault c be   
se5 be/ 9 aft]noon light 9 ! rav9e to ! 
"r1  j s\? ( "s brick-r$ lay]s 9 !      
basalt4    ,movem5t on ! ma9 ,john ,day 
fault to ! s\? appe>s to h rais$  !     

rocks at lea/ #a1jjj feet1 s ! two      
faults h /air/epp$ !  rock lay]s4 ,! ma9
 ,john ,day fault has be5 trac$ ab\t #hj
 miles4    ,illu/ration3 ,fig4          
#b4--,view ( ,m\nt ,v]non ,butte &      
diagram (  fault+ along its s\? slope4  
,illu/ration3     ,illu/ration3 ,fig4   
#c4--,view ( ! ,john ,day fault 9       
,mascall ,=mation  at ! m\? ( ,fields   
,creek1 & its relation to ! /ructure ( !
  ,john ,day ,riv] valley4              
,b4 #add4j    ,fields ,creek ,road4 ,9 !
 road cuts j s\? ( ! highway1 !  ,john  
,day fault 7,fig4 #c7 passes ?r\gh !    
,mascall ,=mation :]e !  slope or dip ( 
! b$s *anges abruptly f g5tly s\?w>d to 
/eeply nor?w>d4 ,! fault cont9ues we/w>d
 "u ! floor ( !  valley4 ,fossil leaves 
& snails c be f\nd 9 ! b$s s\? ( !      
fault1 & #a1jjj feet f>!r s\? v]tical   
,picture ,gorge ,basalt fl[s  are       
expos$4    ,to ! nor? across ! valley at
 ! ,:ite ,hills1 b$s ( ! ,mascall       
,=mation h be5 dropp$ d[n aga9/ !       
,picture ,gorge ,basalt along  ! ,bel%aw

 fault4 ,! ,:ite ,hills are a well-kn[n 
locality =  collect+ fossil leaves4     
,c4 #ach4e to #ace4j    ,v]tical ,ribs4 
,! prom95t v]tical ribs1 visible s\? ( !
 riv]  9 /eep slopes bel[ ! high b5*    
7p$im5t71 are fl[s ( ,picture  ,gorge   
,basalt tilt$ v]tically 9 ! nor? limb ( 
! ,aldri* ,m\nta9  anticl9e4 ,! ,john   
,day fault foll[s ! base ( ! /eep front 
9  :i* ! ribs are expos$4               
,d4 #acb4f    ,volcanic ,a% ,fl[4 ,!    
rimrock nor? ( ! ,john ,day ,riv] betwe5
  "h & ,dayville is a volcanic a% fl[ t 
erupt$ ab\t five million  ye>s ago z r$ 
hot pumice highly *>g$ ) gas4 ,a rapidly
 mov+  inc&esc5t cl\d probably fill$ !  
anci5t ,john ,day ,riv] valley &        
deposit$ a% to a dep? ( m ?an #ajj feet 
ov] a di/ance ( #fj to  #gj miles4 ,z   
%[n 9 ,figure #d1 ! a% fl[ blankets ab\t
 #bjj feet (  gravels t _h be5 deposit$ 
9 ! valley4 ,! rimrock & !  gravels     
above & bel[ x con/itute ! ,rattlesnake 
,=mation4    ,illu/ration3 ,fig4        
#d4--,view nor?we/ across ! ,john ,day  

,riv] valley  t[>d ,picture ,gorge4     
,e4 #abf4j    ,picture ,gorge4 ,visible 
to ! left ( ,picture ,gorge1 f nor?     
ar\nd  to we/1 9 ord] ( _! deposition & 
geologic age f olde/ to  y\nge/1 are !  
,picture ,gorge ,basalt1 ,mascall       
,=mation1 &  ,rattlesnake ,=mation      
7,fig4 #e74 ,! ,picture ,gorge ,basalt  
fl[s & a%y  b$s ( ! ,mascall ,=mation 7 
tilt$ s\?w>d toge!r & erod$  be=e !     
,rattlesnake ,=mation 0 laid d[n        
horizontally across !m4  ,picture ,gorge
 & ! pres5t valley 7 !n cut by ! ,john  
,day ,riv]  aft] ! ,rattlesnake ,=mation
 _h be5 tilt$ 9 its turn4 ,! five  b5*es
 or t]races on ! basalt j ea/ ( ,picture
 ,gorge m>k  tempor>y halts 9 d[ncutt+ (
 ! ,john ,day ,riv]4                    
,f4 #abb4j    ,?omas ,condon ,viewpo9t1 
,john ,day ,fossil ,b$s ,/ate ,p>k4 ,f  
,picture  ,gorge to ! cliffs opposite1 !
 ,picture ,gorge ,basalts & v>icolor$   
a% b$s ( ! ,john ,day ,=mation rise     
toge!r ne>ly #bjjj feet4 ,!  basalt t   
caps ,%eep ,rock is an erosional        

remnant4 ,! l[] b$s 9  ! ,john ,day     
,=mation are color$ r$ by clay erod$ f  
?ick soil on  ! ,cl>no ,=mation1 :i* is 
expos$ 9 ! f>!/ r$ hill4 ,!  soil 0 =m$ 
by tropical wea!r+ "s #cj-ce million    
ye>s ago1  be=e ! ,john ,day ,=mation 0 
laid d[n4 ,fault+ on a small scale  is  
illu/rat$ 9 ,%eep ,rock1 :]e ! ?ick     
olive-drab a% fl[ 9 !  middle ( ! ,john 
,day ,=mation is (fset #ge-ajj feet     
7,fig4 #f74 ,!  fault slopes ab\t #de   
ea/w>d4 ,ab\t two miles d[n/ream1       
l>ge-scale  movem5t on two faults has   
dropp$ ! basalt fl[s 9 ,middle ,m\nta9  
#bjjj-bejj feet4 ,"o ( ! faults foll[s  
along ! up/ream base (  ,middle ,m\nta9 
7,fig4 #f74    ,illu/ration3 ,fig4      
#e--,nor?-s\? section along ! ,john ,day
 ,riv]  ?r\gh ,picture ,gorge & ,middle 
,m\nta94    ,illu/ration3 ,fig4         
#a4--;,geologic map ( ! ,john ,day      
,c\ntry %[+ log  r\te4                  
,high]-,resolution ,map                 
,g4 #aah4g    ,munro ,area1 ,john ,day  
,fossil ,b$s ,/ate ,p>k4 ,! valley ( !  

,john  ,day ,riv] has be5 wid5$ to ne>ly
 five miles by erosion 9 ! ,john  ,day  
,=mation4 ,l>ge tilt$ slide blocks ( !  
,john ,day ,=mation &  basalts jumbl$   
toge!r %[ h[ important l&slid+ ( s(t b$s
  "u h>d rocks c be 9 wid5+ valleys4    
,illu/ration3 ,fig4 #f4--,%eep ,rock f  
,?omas ,condon viewpo9t4    ,"h "o c    
appreciate ! regul>ity & ext5t ( basalt 
fl[s ( !  flood or plateau type1 :i* =m 
! ,columbia ,plateau4 ,individual fl[s  
h be5 trac$ #ajj miles4 ,travel]s w see 
few o!r rocks betwe5  "h & ,! ,dalles1  
,w5at*ee1 ,p5dleton1 or ,spokane z !y   
cross  p>ts ( ! ,columbia ,plateau4     
,h4 #aaf4b    ,ca!dral ,rock4 ,! bluff  
call$ ,ca!dral ,rock is ! front face ( a
  l>ge block ( ! ,john ,day ,=mation t  
has slid f ! we/ 7,fig4  #g74 ,inside ! 
next horse%oe b5d d[n/ream a l>ge mass (
 basalt is  tilt$ d[n aga9/ ,ca!dral    
,rock4 ,f ! highway #a4a miles f>!r     
nor? "o c see ! side ( ! tilt$ block    
along ! riv]1 & !  same two prom95t r$ &
 olive-drab a% lay]s 9 ! high bluff f   

:i* ! block slid4 ,! horse%oe b5d 0 =m$ 
z ! riv] 0  pu%$ ea/w>d by ! nose ( !   
l&slide4    ,illu/ration3 ,fig4         
#g4--,view ( ,ca!dral ,rock & diagram ( 
l&slid+4    ,illu/ration3               
,j4 #ajg4j    ,kimb]ly ,dike4 ,! l[     
bluff across ! riv] is =m$ by a v]tical 
dike ( basalt :i* is ab\t #fj feet wide4
 ,?is dike cuts ?r\gh !  ,john ,day     
,=mation &1 f>!r nor?1 ! ,picture ,gorge
 ,basalt 7,fig4 #h  74 ,x crosses ! riv]
 valley diagonally & c be trac$ ne>ly   
f\r  miles4 ,! dike is =m$ ( once-molt5 
rock t 8froze0 9 a fissure  :i* 0 a     
*annelway = lava t f$ a fl[ on ! e>?'s  
surface4  ,_m simil> dikes are visible  
along ! road ea/ ( ,kimb]ly4 ,!         
basaltic magma is believ$ to h orig9at$ 
at dep?s ( #dj miles or  m )9 ! "p ( !  
e>? call$ ! mantle4      7,at #aje4c    
turn ea/ on ,/ate ,highway #djb along ! 
,nor? ,=k ( !  ,john ,day ,riv]7        
,illu/ration3 ,fig4 #h4--;,basalt dike  
two miles s\? ( ,kimb]ly4               
,k4 #e4j    ,basalt ,dike4 ,a basalt    

dike #ae feet wide cuts basalt fl[s 9   
bluffs  nor? ( ! road & =ms a wall #bj  
feet high 9 places2 x is visible  also  
across ! riv]4                          
,l4 #aa4b    ,p>allel ,dikes4 ,two      
prom95t p>allel dikes1 among o!rs1 =m   
cre/s ( hogbacks s\? ( ! riv]4 ,a small 
tap]+ dike cuts p9k  & :ite b$s ( !     
,john ,day ,=mation 9 ! riv] bluff4 ,?is
 dike  is ! s\?we/ end ( an irregul>    
intrusive mass ( basalt 9 :i*  ! riv]   
has cut a /eep-wall$ gorge4             
,m4 #ac4b    ,basalt ,intrusion4 ,! road
 is cut ?r\gh #cjj feet ( basalt intrud$
  into ! ,john ,day ,=mation4 ,bo?      
contacts are well expos$4 ,!  basalt--:5
 molt5--bak$ & r$d5$ #c to #f in*es ( ! 
adjac5t  b$s4    7,at #ac4i ! highway   
crosses ! ,nor? ,=k ( ! ,john ,day ,riv]
 &  foll[s ! ,cottonwood ,creek         
,valley47                               
,n4 #ah4j    ,irregul> ,dikes4 ,above ! 
highway sev]al small irregul> basalt    
dikes cut ! :ite b$s ( ! ,john ,day     
,=mation4 ,p>ts ( ! l>ge/  dike are #aj 

to #ae feet high4                       
,o4 #bj4a    ,cottonwood ,creek ,valley4
 ,! view nor?we/w>d d[n ,cottonwood     
,creek  t[>d ,monum5t 7,fig4 #i7        
exemplifies ! developm5t ( broad valleys
 by  erosion 9 s(t b$s ( ! ,john ,day   
,=mation "u ! g5tly w>p$  ,picture      
,gorge ,basalt4 ,to ! s\?1 ! valley ends
 aga9/ massive  rocks ( ! ,cl>no        
,=mation :i* 7 rais$ z a block by       
movem5t  along ! ,hamilton fault4 ,! r$ 
b$s are 9 ! l[] "p ( ! ,john  ,day      
,=mation4 ,note ! contra/ betwe5 !      
irregul> massive intrusion  9 ! valley  
bottom we/ ( ,monum5t & ! ?9 regul>     
basalt fl[s4    ,illu/ration3 ,fig4     
#i4--,nor?we/ view d[n ,cottonwood      
,creek t[>d  ,monum5t4    ,on y\r "r1 ! 
irregul> contact betwe5 ! ,john ,day    
,=mation &  ,picture ,gorge ,basalt     
reveals an anci5t l&scape buri$ "u lava 
fl[s 7,fig4 #aj74 ,"s ( ! fl[s w$ge out 
aga9/ =m] hillsides  & "o1 m>k$ by ! dry
 falls1 fills an old valley4    ,= !    
next two miles1 to ! ,sunk5 ,m\nta9     

viewpo9t1 ! road w9ds  ?r\gh l&slides 9 
! ,john ,day ,=mation & ,picture ,gorge 
,basalt4    ,illu/ration3 ,fig4         
#aj4--;,anci5t l&scape on ,john ,day    
,=mation buri$  "u ,picture ,gorge      
,basalt4                                
,p4 #bb4j    ,sunk5 ,m\nta94 ,a small   
l&slide 9 ! l[] "p ( ! ,john ,day       
,=mation is call$ ,sunk5 ,m\nta94 ,:5 ! 
valley wall 0  ov]-/eep5$ by normal     
/ream erosion1 ! jumbl$ mat]ial 9 !  l[]
 "p broke away & slid d[n f ! /eep b>e  
slopes above4  ,abs5ce ( tilt$ trees    
indicates t ! slide is n v active n[4   
,! b>e 8badl&0 slopes are be+ erod$ by  
ra9 wa%4 ,! cliffs (  ! ,john ,day      
,=mation1 :i* ! road climbs half a mile 
f>!r ea/1  are ! result ( rapid b normal
 headw>d erosion by ! creek4            
,ev5tually1 because ( its l[] elevation 
& /eep] gradi5t1 ?is  bran* (           
,cottonwood ,creek w int]cept & behead  
,de] ,creek j  ea/ ( ,hamilton4 ,a      
photog5ic p]spective view ( ! future    
/ream  piracy c be se5 f ! road on !    

ridge j s\? ( ,sunk5  ,m\nta91 ab\t a   
mile & a half f ! highway4              
,q4 #bf4d    ,long ,creek ,m\nta94 ,an  
uplift$ block ( ,picture ,gorge ,basalt 
#adjj-aejj feet ?ick =ms ,long ,creek   
,m\nta92 ,r\nd ,bas9 is erod$ 9  ! ,john
 ,day ,=mation on :i* ! basalt re/s     
7,fig4 #aa74 ,! base (  ! basalt c be   
se5 9 road cuts on ei!r side ( ,bas9    
,creek4 ,!  ,hamilton fault foll[s !    
gul* to ! left j bel[ ! p>k+  area1 goes
 up ! tree-fill$ gul* across ,bas9      
,creek1 along ! l[  ridge at ! nor!a/   
edge ( ,r\nd ,bas91 & !n along ! nor!rn 
foot ( ! m\nta94 ,! small slab ( basalt 
s\? ( ! fault 9  ,bas9 ,creek has be5   
tilt$ ab\t #aj nor? by d[nw>d drag along
 !  fault4 ,! ,hamilton fault sy/em     
ext5ds ab\t #ae miles f>!r ea/4      7,9
 ,long ,creek turn "r--s\?--on ,u4 ,s4  
,highway #cie74    ,illu/ration3 ,fig4  
#aa4--,view ( ,long ,creek ,m\nta9 &    
,r\nd ,bas91 &  diagram ( ! geologic    
/ructure4    ,illu/ration3 ,fig4        
#ab4--,nor?-s\? section across ,fox     

,valley1 %[+  ! fault$ bas9 /ructure4   
,r4 #ii4e    ,fox ,valley4 ,d[n-w>p$    
fl[s ( ,picture ,gorge ,basalt dip t[>d 
,fox  ,valley f all sides to =m a bas9  
7,fig4 #ab74 ,! valley is erod$  out (  
a%y b$s & gravels ( ! ,mascall ,=mation 
:i* fill !  c5t] ( ! bas9 to an e/imat$ 
dep? ( #ajjj-abjj feet4 ,faults =m  p>ts
 ( ! nor!rn & s\!rn bord]s ( ! bas94 ,! 
/raight1  timb]$1 nor?w>d-fac+ /eep     
slope less ?an a mile s\!a/ ( !         
viewpo9t m>ks a fault4                  
,s4 #ahj4c    ,/rawb]ry ,range4 ,?is    
range & ! ,aldri* ,m\nta9s =m a m\nta9  
range #ej miles long2 ,/rawb]ry ,m\nta91
 altitude #ijch feet above sea  level1  
is its highe/ peak4 ,! ea/]n two-?irds (
 ! ,/rawb]ry  ,range 7,fig4 #ac7 0 rais$
 z a great block by uplift on ! ,john   
,day  fault1 :i* foll[s ! nor!rn base ( 
! m\nta9s4 ,! rocks 9  ,/rawb]ry ,m\nta9
 & to ! ea/ are mo/ly lavas :i* p\r$ out
  ov] ! l&1 :]eas ! ,canyon ,m\nta9 "p (
 ! range consi/s (  gabbro & p]idotite  
:i* 7 intrud$ at great dep?1 l granite4 

,! valleys 9 ! high] p>ts ( ! range1    
above ab\t #ejjj feet1  7 wid5$ f n>r[  
,v's to _! broad ,u pr(iles by glaci]s  
dur+ ! ,plei/oc5e ,epo*1 or ,great ,ice 
,age4 ,! alluvial fans  7,rattlesnake   
,=mation7 9 front ( ! m\nta9s 7 built up
 (  b\ld]y gravels & f9] s$im5ts4 ,^!   
mat]ials 7 erod$ f  ! m\nta9s1 c>ri$ by 
/reams d[n ! /eep n>r[ canyons1 &       
spread out on ! valley floor4 ,because  
mu* m mat]ial came into !  ,john ,day   
,riv] f ! ,/rawb]ry ,m\nta9s ?an f ! l[]
  m\nta9s to ! nor?1 ! riv] 0 pu%$ to ! 
nor? side ( its  wide valley4 ,fault+ & 
erosion h completely de/roy$ ! cones (  
! volcanoes f :i* ! volcanic rocks 7    
erupt$ 9 ,mioc5e &  ,plioc5e "t4        
,illu/ration3 ,fig4 #ac4--,panorama ( ! 
,/rawb]ry ,range & ! ,john  ,day ,riv]  
valley f ! nor?4    ,illu/ration3 ,fig4 
#ad4--,section ?r\gh ! ,/rawb]ry        
,m\nta91 along  ,/rawb]ry ,creek4       
,?is image 9 high] resolution           
,/rawb]ry ,lake & ,vic9ity4 ,at         
,/rawb]ry ,camp1 ab\t #ab miles s\?  (  

,prairie ,city1 ! broad floor & /eep    
walls ( ,/rawb]ry ,creek  valley        
indicate t ! valley has be5 glaciat$4 ,!
 precipit\s  cliffs & r\nd$ valley      
bottom above ,/rawb]ry ,lake are        
*>act]i/ic ( glaciat$ m\nta9s 7,fig4    
#ae74 ,/rawb]ry ,lake is  damm$ by      
l&slides :i* probably came f ! we/ wall 
( !  valley aft] ! glaci] melt$ & left !
 valley wall ov]-/eep5$4  ,! hummocky   
surface & blocky mat]ial 9 ! slide are  
well %[n  along ! la/ half mile ( !     
trail to ,/rawb]ry ,lake4 ,/rawb]ry     
,falls m>k ! front ( a glacial /ep ov] a
 massive fl[ ( platy  &esite4 ,little   
,/rawb]ry ,lake is damm$ by a l[ glacial
 mora9e4    ,illu/ration3 ,fig4         
#ae4--,/rawb]ry ,lake1 ! glaciat$ valley
 (  ,/rawb]ry ,creek1 & cirque walls =m$
 by ! ,/rawb]ry volcanic  plug4    ,mo/ 
( ! lavas 9 ! ,/rawb]ry ,m\nta9s 7      
erupt$ f a  c5tral v5t ab\t #djjj feet 9
 diamet] :i* is expos$ 9 ! cliffs  above
 ,little ,/rawb]ry ,lake4 ,! p9nacles   
kn[n z 8,rabbit ,e>s10  above ! prom95t 

talus 9 figure #ae1 are ( v5t breccias t
  consi/ mo/ly ( weld$ blocks (         
scoriace\s basalt1 b also conta9        
volcanic bombs :i* 7 bl[n out z blobs ( 
fluid lava4 ,huge blocks  ( ! breccia h 
fall5 onto a g5tle b>e slope we/ (      
,little  ,/rawb]ry ,lake4 ,! massive1   
v]tically-jo9t$ cliffs are =m$ (  basalt
 :i* cool$ sl[ly & =m$ a plug 9 ! ?roat 
( !  volcano aft] ! eruptions ceas$4 ,! 
?9 irregul> scoriace\s  &esite fl[s1 :i*
 are expos$ 9 ! cliffs ea/ ( ,little    
,/rawb]ry ,lake adjo9+ ! plug1 contra/  
/rik+ly ) ! massive  ev5 fl[s ( !       
,picture ,gorge ,basalt4    ,tilt+ ( !  
,/rawb]ry ,m\nta9 block is %[n by !     
s\?w>d dip  ( all ! fl[s 9 ! area4 ,!   
fl[s 9 ! cliffs we/ ( ,/rawb]ry  ,lake1 
= example1 orig9ally mu/ h slop$ nor?w>d
 away f !  v5t :]e !y erupt$4 ,_! pres5t
 s\?w>d dip ( ab\t #ae  !re=e indicates 
t !y h be5 rotat$ m ?an #ae by  fault+1 
p>tly along ! nor!rn edge ( ! m\nta9    
range4 7,fig4 #ad  74                   
,select$ ,ref]5ces ,to ,detail$ ,reports

        ,u4 ,s4 ,geological ,survey     
,maps3    ,no4 #a-ddg ,geologic ,map ( !
 ,canyon ,city quadrangle1 nor!a/]n     
,oregon1 by ,c4 ,erv9 ,br[n & ,t4 ,p4   
,?ay]1 #aiff4 ,! map            cov]s ! 
entire region at a scale ( "o in* equals
 #d            miles4    ,,gq-#dch      
,geologic ,map ( ! ,aldri* ,m\nta9      
quadrangle1 ,oreg41 7)            text7 
by ,t4 ,p4 ,?ay] & ,c4 ,erv9 ,br[n1     
#aiff4    ,,gq-#edh ,geologic ,map ( !  
,m\nt ,v]non quadrangle1 ,oreg41 7)     
text7            by ,c4 ,erv9 ,br[n &   
,t4 ,p4 ,?ay]1 #aiff4    ,,mf-#ea       
,prelim9>y ,geologic ,map ( ! ,john ,day
 quadrangle1 ,oreg41 by            ,t4  
,p4 ,?ay]1 #aief4    ,u4 ,s4 ,geological
 ,survey ,pr(essional ,pap]s3    ,no4   
#eej-;,c ,local ?ick5+ ( basalts &      
silicic volcanism 9 !            ,canyon
 ,city quadrangle1 ,oreg41 by ,t4 ,p4   
,?ay] & ,c4 ,e4            ,br[n1 pages 
,c#gc-;,c#gh1 #aiff4                    
7,f mat]ial provid$ by ,?omas ,p4 ,?ay]7
    ,illu/ration3       ,z ! ,nation's  

pr9cipal cons]vation ag5cy1 ! ,dep>tm5t 
( !  ,int]ior has basic responsibilities
 = wat]1 fi%1 wildlife1 m9]al1  l&1 p>k1
 & recreational res\rces4 ,indian &     
,t]ritorial affairs  are o!r major      
conc]ns ( ,am]ica's 8,dep>tm5t (        
,natural ,res\rces40    ,! ,dep>tm5t    
works to assure ! wise/ *oice 9 manag+  
all our  res\rces s ea* w make its full 
contribution to a bett] ,unit$          
,/ates--n[ & 9 ! future4                
,transcrib]'s ,notes      --,sil5tly    
correct$ sev]al typos4    --,provid$ all
 images resiz$ & ori5t$ = use on a      
portable e,book    read]4    --,provid$ 
clickable l9ks to high]-resolution      
v]sions ( detail$    images4