(>I.li_l,lNl A(.I dK I.AKK AGASSI/. 57 



THE LINEAGE OF LAKE AGASSIZ. 



-lAs/r.u/., 



As LaUr Wimii|H'o- has succeeded Lake Agassi/, so tin! 

 lattei- may trace its liiieanH' hack three aiics, ms follows: 



Fir.^f. When the ic-e sheet tilled the hasin> of Lake A,<ras- 

 si/ and blocked the \ alley coiiiieetiiio- the IJcd Kixcr and 

 Jaini>s River valleys. Lake Dakota extended 1 K) niile> loni:-, 

 ten to thirty miles l.road from Oakes to .Mitchell, Dak. 

 A le\-el [)lain loODfeet altoN'e t!ie sea now occupies its formei" 

 hasin. 



Seconil . When the Ice Sheet jccupied the second or(iray 

 Moraine in the .lames \'allev, tillinii- the hasin of Lake, 

 Dakota, there was a (|uite extensive White Lake, oceupvini; 

 the hasin of a diminutixc descendant of t!iat name in Aurora 

 County, Dak., its altitude about l.")"<7 feet. Also, a >maller 

 and more tl'ansieut lake James Lake ^southwest of 

 Mitchell, ext.'iidinii- into Dou'jlass Countv: the proent alti- 

 tude of its western border is about 14.U) feet. 



'I'Ji/nl. Still earliei', when t!ie ice occaipied the lirst oi 

 Altamoni Moi-aine, or as some leadini:- irhicialist- would say 

 far antecedent to that tinu', durini;- the latter part of a first 

 i:lacial cpocli, a ^I'cat Ixxly oj water occupied all eastern 

 Nebraska, western Iowa and adjacent pai't> of Miniu'sota and 

 Dakota. lis most diaracterisl ir ,|,.p,,>it is the he^s. This 

 lake was named Lake Missom-i al)out ten years ai^o ( rifle I'roc. 

 A. A. A. S. I,s77. p. I'll] ). The ooiuM-al level of the hess 

 slopt^s >outhwar(l. two feet to the mile: and eastward tlireo 

 to five feet, west of the Missouri. ;ind one to two feet east of 

 it. Its altitude is l-SOO feet in Wayne ('((unty. Neb.. :ind 

 100') feet at .Marysville. Missouri. 



(pRor. 1. A. S., 18S7-0.J =v |Kcb. 10. iSSo-l 



