Bollettino della Società geologica d'America . Ha spinto contro il bordo orientale del Coteau Missouri in un modo simile, ma il coteau è stato più interrotto, o meno continuo, in modo da non offrire la stessa resistenza come in NorthDakota. Inoltre, si stava muovendo in una valle fluviale su depositi alluvionali, che senza dubbio ha fatto i suoi progressi più facile e veloce. Terzo rapporto biennale del North Dakota Geol. Surv., pp. 80-8C. Journal of Geology, vol. 23, pp. 53-55. Prove FEOM SOUTH DAKOTA 477 Da questi fatti sarà prontamente visto che le principali relazioni del Missouri Eiver al ghiaccio-lei

• Collaboratore: The Reading Room / Alamy Foto Stock
• ID dell’immagine: 2AMYM4T
• Dimensioni dei file: 7,2 MB (528,1 KB Download compresso)
• Liberatorie: Modello - no | Proprietà - no
• Dimensioni: 1512 x 1653 px | 25,6 x 28 cm | 10,1 x 11 inches | 150dpi

Altre informazioni

Questa foto è un'immagine di pubblico dominio, il che significa che il copyright è scaduto o che il titolare del copyright ha rinunciato a tale diritto. Alamy addebita un costo per l'accesso alla copia ad alta risoluzione dell'immagine.

Questa immagine potrebbe avere delle imperfezioni perché è storica o di reportage.

Bulletin of the Geological Society of America . It pushed against the eastern edge of theMissouri Coteau in a similar way, but the coteau was more interrupted, or less continuous, so it did not offer the same resistance as in NorthDakota. Moreover, it was moving in a river valley upon alluvial deposits, which no doubt made its progress more easy and rapid. Third Biennial Report of the North Dakota Geol. Surv., pp. 80-8C. .Journal of Geology, vol. 23, pp. 53-55. EVIDENCE FEOM SOUTH DAKOTA 477 From these facts it will be readily seen that the principal relations ofthe Missouri Eiver to the ice-sheet would be very similar to those inXorth Dakota. The principal difference would be that the ice extended 1 MAP 5HOW1N6 THE PROBABLE HISTORT - or TME FDRMM10N°Vhe:^MIS50URI RIVER50UTh*DAKOTA acTooo. 192EXPLANATIONSLimit o( the glacial driftEdqe of maximum ice sheetv v v*.Morqin of oncient lakes ? • Moraines PRE-WISCONSINWISCONSIN Altamont Gory Ancient Channels TERTIARY ^ PLEISTOCENE , . Altitude, feet obove sea levelEOOQ 1 .< 2 .?. Figure 2.—Map of South DakotaShowing probable history of the formation of the Missouri River in South Dakota. so far south that it did not reach its maximum extent so soon, and themoraines formed would consequently be smaller and less continuous. For our purpose, it will not be necessary to present all the evidencewhich might be stated. We will limit our discussion to two or three ofthe more decisive points. 478 J. E. TODD THE CHAXXEL OF THE MISSOURI RIVER DAMMING OF THE NIOBRARA RIVER Some years ago the writer studied the ancient channels between theStates of Sonth Dakota and Nebraska. The older system included theNiobrara, Ponca, Mosquito, and Choteau creeks. Their altitude wasfrom 100 to 125 feet higher than the present streams occupying thatregion. It is evident that the Niobrara, the larger one, crossed thetrough of the present Missouri a little east of Springfield, swept in abroad curve to the north past the stations of Tabor and TJtica

Parole chiave associate all'immagine

• bookcentury1800
• bookdecade1890
• booksubjectgeology
• bookyear1890