280 T. O. MABRY 



elusive, as where the Brown Loam rests directly upon the pre- 

 Lafayette formations, and there is no trace of the Lafayette 

 left in the vicinity, it is impracticable under such circumstances 

 to say whether the Lafayette once covered the given local- 

 ity and has been entirely removed by erosion, or whether it was 

 never present. Such a state of things is exhibited in many 

 places in the country near New Albany, Miss., and elsewhere. 

 The Brown Loam mantles the hills and dales of this region, rest- 

 ing in many places directly upon the Cretaceous, sometimes upon 

 the Lafayette, as it does elsewhere (as we shall presently see) 

 upon the Lignitic Tertiary, and as it does regularly upon the 

 Lafayette further westward. It cannot be a surface disintegra- 

 tion of the Cretaceous at this place ; but it is seen to be directly 

 continuous with the loam stratum elsewhere observed, and was 

 without doubt formed at the same time and in the same way. 

 (As to the geological relations of the surface soil, Brown Loam, 

 in this region, see also Ag. & Geo/, of Miss., paragraphs 335, 336, 



and 337. PP- I98-I99-) 



But sometimes the Brown Loam rests upon older formations 



once covered by the Lafayette, which has subsequently been 



removed by erosion. There are two lines of evidence : (a) Near 



Oxford, Miss., where the Lafayette is typically developed, it 



attains a maximum thickness of something like 200 feet. But 



towards the east it soon thins out, exposures of the Lignitic 



being quite common within eight or ten miles of Oxford. 



As the region of Flatwoods is approached, the Lafayette 



becomes discontinuous, and patches of it only are to be found 



intercalated between the Brown Loam and the Northern Lignitic. 



The Lafayette seems to give out altogether several miles before 



the Flatwoods are reached. At the exact western limit of the 



Flatwoods, some ten miles west of Pontotoc, on the Pontotoc 



and Lafayette Springs road, several feet of typical brown loam 



are seen to rest directly upon the blue clays of the Lignitic. 



Over the Flatwoods region, here six or seven miles wide, both 



the Brown Loam and the Lafayette are usually absent, the latter 



always, the former occurring in limited patches towards its east- 



