T.i:)r>-r :-.HR.\c '..^ oi ni. mi .-;mi io )) 



THE TERRACES OF THE MISSOURI. 



IIV l'K(»F. j. K. MOOU 



This ]>M)>or I'lix^smtiMl Ihc ro.-wlts of ol^x'-rNM'ilDn^ mndc h\ 

 the uiit'.un", uudcr tlw diivcf ion «!' 1 In- I'uilcd Stjitcs (itM*- 

 3()<i'i(';il Sui'Ncv. Jt trciilcd cspcciaJIv (ilthc pdrtiiMi <«f tlv 

 fixer h'lwcrn the (ircal UiMid :ii:.(J the luoulli uf IIji- PJattc. 



I'hrc;^ ijrouiis (*f ti'rraco wrrc r(':'(?;iiii/!'(|, \ i/ : I'm- Sill tc!-* 

 iMcos, th(> L.'HWcr l><Mi]{Jci\v lrn-;i('cs ;ii/i(J llv"' \l\'^Urv 15.,"j|(J('r\' 

 IciTnccs. 



rh(' ijr.^t iirc less tl\;i)? i wimiI v-l3\ c foct :i1io\(- )(>\\ Watci". 

 Ix'low the mdulh o) l!!c Niohrara. aiiJ ris;- o-raduailv iiort!!- 

 Avard to the iii'ijjlit of aluMit loic IhiikJiccJ aiuJ tliii-tv icrT near 

 the month (if C'rinv ('reck. 'Dm' scvoiid a.Jsc* ris- ud-tliwaiij 

 fi-o;ij ahotit srvcntv iVct ai I'lc Mnxjlli of {')- I*Jat1;\ lo t!irco 

 ]ii!iidiT-d iVi'i alunc Hie (ircal HmhJ. 'J'Ik- thirtJ, wliicls cor- 

 r('s[)onds to the upjxT lijuit <»!' t.'ic (Jrift, hch^w t'lc iiuMith of 

 the Xiohran\, at an altihuic of four hundred and t\vt'Rty-6\-e 

 to four hundve<l :ind l?fty ft vt. i^ tiaeeahle a1 aUout th" same 

 ^'levatioii. nearly to the 5no!ilJj of tlw \\'hil •. IrreijiUaiaties 

 h\ the eUnali<')n and nnniUer of l!u"se terraces were referred 

 to the influerice of tri)»»ta,rie>. and i(f freijnent clnnii-es while 

 the tv\)niiii was iicinu- dcepcjUHi. 



All of t'hem. e.-i)eeia}]y 1 he liia'lier uues. av< hivi;c]y comi^osiHl 

 of Cretaeoons roeks. Al>o\-e 'diesc, ir. lixr IJouMery terraees, 

 tJK're is ijcenerally a thick stratum of V(M,ldish till smuetinn's 

 vsli/jhtly haiKled or stratiti;'d. 'l]\\< i> cuven'd with a stratunt 

 of ,i;-ravel an<l ix.uldcrs, and ahr-xc this is a t!iiel< laytMof yellow 

 silt. Tlie Lcess of l^asttMU Nehraska seems t«t he the continu- 

 ution of tlie siit layei- of ihc u|>})(«r Ikmhh'ry terrace. 



The Silt terrac(>s were referred to recent time; t!ie Lower 

 Bouklery. to the occupation of the .'Second Moraine hy ;iii ice- 

 sheet ; t!ie l'|)|)er Iiouhh'ry IciiMce- tea similar <> •cii])ai ion 

 of the Fii>t .Moi-aine. 



