1:«2, 333] YEU.iAV LOAM. 197 



aud contains the bicarbonates of lime and magnesia feu such an 

 extent, as to be disagreeably perceptible even in the streams of the 

 region. For this reason, cisterns, or wells deep enough to pene- 

 trate tin 1 Grand Grtilf strata, are very generally preferred to the 

 natural waters. It is questionable, however, whether even these 

 are not preferable, as far as health is concerned, to many of the 

 strongly saline and magnesian waters sometimes (ound in deep 

 wells, which contain the sulphates and chlorides, instead of the 

 carbonates, of the above earths (1*316). 



III. THE FELLOW LOAM DEPOSITS, 



332. The yellow, brown, or reddish loams, which have been 

 repeatedly mentioned as forming the surface, and therefore, 

 essentially, the soils ol' the greater portion of the State of -Mississippi, 

 constitute, to all appearance, an independent aqueous deposit. 

 posterior to the Orange Sand and Bluff formation, and anterior to 

 the alluvial formations of the present epoch. The great thickness 

 which this loam stratum attains in some regions, its distinct 

 definition, as well as its comparative independence, as to its char- 

 acter, of the formations immediately underlying, preclude its being 

 claimed as a mere surface disintegration of the older formations. 

 The nature of its materials, and the entire absence of stratification 

 lines distinguish it sufficiently from the Orange Sand, where it 

 immediately overlies the latter ; while the absence of any large 

 amount of lime (except where it is in immediate contact with 

 strongly calcareous formations), the presence of a considerable 

 amount of hydrated peroxide of Iron, as well as the want of proper 

 fossils, as distinctly separate it from the Bluff formation of the 

 Mississippi River. 



I have stated that it is to some extent independent as to its character, of the 

 underlying formations ; i. e. it is not so uniformly dependent upon them as to 

 allow of its being considered (as has been attempted) as a mere surface disinteg- 

 ration, in loco, in the absence of a more general distributive agency, than those 

 which we find at work at the present time. Yet nevertheless, there is a very 

 obvious general correspondence of variation in character, between the older for- 

 mations aud the surface loam, more especially so where the stratum of the 

 latter is thin ; a circumstance which cannot fail to force itself upon the atten- 

 tion of every one in the study of the soils of the State. In view of the intimate 

 connection existing between the latter and the loam stratum, 1 shall leave the 

 special description of its variations in different districts, for the Agricultural 

 portion of the present Report, where these will necessarily be mentioned ; and 

 will only give in this place some generalities concerning its geological relations. 



333. From the appearance of the loam stratum even on high ridges and 

 elevated uplands, it is obvious that its deposition took place, in part at least, 

 anterior to the great denudations which have produced the present surface 

 conhguration ; nevertheless, its increasing thickness as we approach the imme- 

 diate valley of the Mississippi, shows, as in the case of the Bluff formation, that 

 this great channel was already in existence. On the Tombigbee, and on the 

 lower Tallahatchie, Yallabusha, and Big Black, a similar increase in the thick- 

 ness of the loam stratum may be observed. But on the smaller watercourse, 

 this is the case only to a very limited extent, showing that although at the time 



