1343, K44] SECOND BOTTOM — ALLUVIUM 1 . 201 



and clayey bands, of their formation in flowing water ; yet it is 

 evident that the streams in their present condition could not have 

 formed them. They seem to be a parallel, in many respects, to the 

 " Bottom Prairie" of Missouri (Rep. of the Geol. Surv. of Mis- 

 souri, p. 66, if.) 



Sometimes (as on the Tombigbee) they slope down gradually into the first 

 bottom ; but more commonly (Big Black, Pearl, Pascagoula Rivers) they fallofF 

 with rather a sudden descent of 3 to 4 feet, and sometimes more. Their soil 

 is most generally lighter than that of the first bottom of the same stream, and 

 much poorer in vegetable matter. On Yockan^okana and Big Black they are 

 usually whitish, as also on upper Pearl River ; on Yallabusha, lower Pearl, and 

 ou the Tombigbee River, the soil is commonly formed of a yellow loam, some- 

 what lighter than that of the bordering hills, and of a paler hue ; but in 

 general, there is a very obvious correspondence between the material of the body 

 of the hills, and that of the second bottom deposits ; showing that at the time of 

 their formation, the denudations were cutting deeply into the surface. Not 

 unfrequer.tly, we find the level surface of these "hommocks" interrupted by 

 hillocks or ridges of more ancient formations — especially of the Orange Sand — 

 which, being composed of materials opposing considerable resistance to denu- 

 dation, were surrounded and partially covered over by the newer deposits. 

 Examples of this kind are of common occurrence in the level region E. of the 

 Tombigbee, in Monroe and Lowndes (^535), where pebbly hillocks of the Orange 

 Sand age, and others belonging to the Tombigbee Sand Group of the Cretaceous, 

 appear like islands in the plain. 



343. Since the Second Bottoms, like the Yellow Loam, are of necessity 

 mentioned in connection with the soils, in the Agricultural portion of the Report, 

 I shall not enter here upon more special descriptions of these deposits, which 

 appear to have been the first result of the more active denudations which suc- 

 ceeded to the deposition of the loam, and scooped out the bulk of the valleys of 

 the minor streams also, in their present place ; though none of these ever, at 

 the present time, fill the whole of the space which, as the nature of the deposit 

 proves, they once must have occupied. — How much of the Mississippi Bottom 

 deposits may be referrible to the same period, I am unable to say, not having, as 

 yet, had any opportunity of personal observation. It seems that near the sea- 

 shore the period here referred to is represented by the sands forming the " Pine 

 Meadows" and part of the " Sand Hommocks ;" a specimen of whose stratifica- 

 tion is given in Diag. No. 3 (ITol), which see. 



V. THE ALLUVIAL DEPOSITS. 



344. These include all the soils, first-bottom deposits, sand-bars, 

 etc., now in progress of formation, or attributable to causes now in 

 action, and will of necessity be treated of at length and in detail, 

 in the Agricultural portion of the present Report ; they need not, 

 therefore, find any lengthy discussion here. Their useful materials 

 are our arable soils, greatly surpassing in value and importance the 

 richest mineral deposits of the older formations ; and the doctrine 

 which, in treating of these latest formations, corresponds to that 

 of the mining and smelting of the rocks and ores of the former ; 

 which teaches us how to utilize in a rational and economical 

 manner, the resources of the important deposits in question, is that 

 which shall next occupy our attention : Scientific Agriculture. 



