THE BROWN OR YELLOW LOAM OF NORTH MIS- 

 SISSIPPI, AND ITS RELATION TO THE NORTH- 

 ERN DRIFT. 1 



OUTLINE. 

 I. General characteristics of the Brown or Yellow Loam. 

 II. Its stratigraphic relations and its distribution in north Mississippi. 



A. Its relations to the Lafayette. 



Unconformity between the Brown Loam and the Lafayette proper indicated byr 

 (i) The fact that wherever the Lafayette occurs in force, covered by the loam, 

 the greater part of the present surface relief is due to the irregular contours 

 of the Lafayette, rather than to varying thickness of the former, resulting 

 from recent erosion : topographic relief of the Lafayette greater than that 

 of the Brown Loam. 



(2) (a) The feathering out of the Lafayette, and its alternate disappearance 



and reappearance eastward and northeast from Oxford, Miss., thus 

 leaving erosion remnants intercalated between the Brown Loam and 

 pre- Lafayette formations. 

 (b) The presence in the surface formation of northeast Mississippi, where, 

 in many places, the Lafayette is now absent, of materials similar to 

 those of the Lafayette where typically developed. 



(3) The degree of oxidation produced in the Lafayette prior to the deposition 

 of the Brown Loam. 



(4) The occasional presence of thin patches of a seemingly distinct formation 

 intercalated between the two, composed of materials similar to those of 

 the Lafayette, but unconformable alike with the Lafayette below and with 

 the Brown Loam above, thus indicating, probably, two erosion intervals of 

 greater or less duration between the time of the deposition of the Lafay- 

 ette and that of the Brown Loam. 



(5) The character of fossil plants found in bowlders of clayin this intermediate 

 formation, near Oxford, Miss., and derived presumably from the Lafayette. 



Summary : The preglacial age of the Lafayette. 



B. Its relation to the Loess (01 Bluff formation of Hilgard). 

 III. Origin and age of the Loess Loam. 



A. Lower limit of the formation in north Mississippi. 



B. Upper limit in the same region. 



C. Conditions under which the formation was deposited. 



D. Subsequent alteration. 



'This paper is based upon a series of personal observations extending continu- 

 ously from Riverton, Alabama, to Memphis, Tennessee, in a crescentic curve passing 



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