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in some of them, are noticed to low-water mark. The last bed, 

 in the series visible above water, is an indurated clay, of unknown 

 thickness, which is said to contain bones of the Zeughdon, and 

 apparently belongs to the tertiary formations. 



Dr. Binney said that, in the course of the examination, he had 

 been struck with the near resemblance of the upper beds of the 

 bluff to the deposit in the valley of the Rhine, called locally 

 loess, as described by Mr. Lyell. Like that, they consist of a 

 yellowish pulverulent loam filled with land-shells, and calcareous 

 concretions ; and he supposed them to be due to similar causes. 

 The physical characters of the deposit, and its contents, go far 

 to account for its origin. The Mississippi, draining, through ten 

 thousand channels, a vast geographical area, bears upon its sur- 

 face the light objects washed down the streams of a large part of 

 the central portion of North America, and holds suspended, in its 

 waters, comminuted particles, derived from the various soils 

 and calcareous strata through which its tributaries pass. During 

 the rainy seasons, its accumulated waters rise above its banks, 

 and, spreading over the low country, form shallow lakes, where 

 they remain until the river again subsides within its banks. The 

 deposit, left by the retiring waters, is a calcareous loam, and 

 often resembles precisely the loamy deposhs of the bluff. Like 

 these, too, it contains land and fluviatile shells left on the surface 

 of the deposit, and sometimes the carcasses of animals which 

 have been turned aside from the main current of the river. We 

 have only to suppose then the region, in which the bluff deposit 

 prevails, to have been formerly but a little raised above the 

 ordinary level of the Mississippi, and, consequently, to have been 

 subject to frequent inundation by the rising of its waters, or that, 

 from the damming up of its waters below, the river spread out into 

 an extensive lake, to have at once a cause adequate to such a 

 deposit as that presented by the strata in question. The present 

 position of these beds is easily accounted for by their gradual 

 uplifting through earthquake action, a theory by no means a 

 violent one, as the valley of the Mississippi is one of the theatres 

 of modern earthquakes, and has been disturbed by them at a 

 period yet very recent. 



Dr. B. stated it to be his opinion, derived from facts that had 

 come to his knowledge, and from a few published remarks that 



