BROWN AND YELLOW LOAM OF NORTH MISSISSIPPI 28 1 



ern border. Both formations seem to be found again in the 

 Pontotoc Ridge and Buncombe Hills, as already noted; but the 

 Lafayette soon gives out and seems not to appear again, at least 

 not strongly and typically developed. For example, over the 

 greater part of Union, Prentiss, and Tishomingo counties, the 

 Brown Loam rests upon formations older than the Lafayette. 

 Frequently the Brown Loam has been removed by erosion, and 

 the "Rotten" Limestone, Selma, or Tombigbee Chalk comes to 

 the surface. Exposures of this latter formation are quite com- 

 mon in the prairie region, as is well shown around Booneville, 

 Baldwyn, Marietta Springs, etc. 



On a hilltop about fourteen miles from Booneville and six- 

 teen miles from Iuka,' on the old Booneville and Iuka road, sev- 

 eral feet of Yellow Loam repose directly upon stratified, blue, 

 pyritiferous clay of the Eutaw (?) group. 



At Bay Springs, in southwest Tishomingo county, the Brown 

 Loam rests either directly upon Sub-Carboniferous sandstone or 

 there is a thin intervening stratum of pyritiferous Eutaw (?) 

 clay — the source of the chalybeate waters of the springs. 

 (6) While there is plenty of orange-colored sand in east Pren- 

 tiss and in west Tishomingo counties, nowhere in this region 

 did we find materials of undoubted Lafayette age in situ, though 

 it seems likely that the Lafayette once covered this area, and 

 that small patches of erosion remnants may still exist, because 

 materials similar to those found in the Lafayette further west 

 are here found to a greater or less extent scattered irregularly 

 through the Brown Loam. The quartzose pebbles of Tisho- 

 mingo county, for example, described by Hilgard (Ag. & Geol. of 

 Miss., i860), and referred to the Lafayette epoch, seem to 

 occupy an entirely different stratigraphic position from the 

 majority of those in the western region, i. e., from Memphis, 

 Tenn., to Grenada, Miss., and southward, which are evidently of 

 Lafayette age. In the former region these pebbles are found 

 intermingled with the Brown Loam, as shown in many places near 

 Iuka and elsewhere, while in the latter region they are invaria- 

 bly below the Brown Loam, sometimes in apparent local con- 



