BROWN AND YELLOW LOAM OF NORTH MISSISSIPPI 285 



ing an exposure of thirty to thirty-five feet, shows a section very 

 similar to the one just described, except that the middle mem- 

 ber here consists of eight to twelve feet of clay bowlders, large 

 and small, rounded and angular, mixed indiscriminately with 

 sand. This section shows : 



Fig. 1. — Section near the depot at Oxford, Mississippi, showing two members of 

 the Columbia Formation and their relation to the Lafayette, (a) Yellow Loam ; (d) 

 fossiliferous clay bowlders and sand ; (r) cross-laminated Lafayette Sand. 



[a) At top, 0-8 feet of Yellow Loam. 



(d) 8-12 feet of clay bowlders and sand. 



(V) At base, 0—12 feet of cross stratified Lafayette sand. 



Here the three formations are very distinct lithologically, 

 and there is no evidence of the gradation of one into another 

 either in a lateral or in a vertical direction. 



The top stratum (#) is a typical loam, while (&) consists 

 of sand mixed with clay bowlders, rounded and angular, varying 

 in size from mere pellets up to slabs one to two feet thick, four 

 to six feet long, and of unknown width, but presumably of not 



