THE LOESS OF NATCHEZ, MISS. 325 



of fresh-water shells . . . The Natchez bluff is about 150 feet 

 in height. The lower part is composed of gravel and sand, 

 containing many corals and other fossils. Next comes a stra- 

 tum of clay, rich in fossils of large extinct species of quad- 

 rupeds. The top is made up of yellow loam, sand, and clay, 

 also fossiliferous." 



Here again the authors included various deposits under one 

 name. Evidently only the uppermost portion is loess. If the 

 "yellow loam" of^Vicksburg is loess, as seems probable, the 

 statement that it contains "vast numbers of fresh-water shells" 

 is a myth, and the authors evidently knew nothing of the 

 habits of these snails. Of a similar nature is Foster's state- 

 ment* that the shells of the loess "are all of fresh-water origin." 

 Foster subsequently,"!" however, speaking of the southern loess, 

 says: "The Tertiary beds are of marine origin, while those of 

 the loess are of fresh-water, and contain numerous shells, all 

 of which are of terrestrial origin." 



On p. 61 of the same work Foster also discusses the reported 

 occurrence of human remains in the Natchez loess, with this 

 conclusion: "The probabilities are a hundred to one, that this 

 bone was not of Bluff formation."! 



Dr. A. Binney's, and Humphreys and Abbot's reports of 

 marine fossils from the loess are probably referred to by Hil- 

 gard§ when, discussing the Natchez Bluff, he says that "ma- 

 rine shells have also been reported as occurring." He, how- 

 ever, adds that there are no fossiliferous marine deposits. 



Finally Dana|| speaking of the "Bluff formation" states that 

 "south of New Orleans there are marine shells," evidently 

 confusing the Gnathodon beds with loess. 



*J. W. Foster, The~Mississippi Valley, — 1869; p. 345. 



t Prehistoric Races of the U. S. of America, — 1873; p. 59. 



tThis bone was also discussed by Lyell in his "Second Visit to 

 America," vol. II, p. 1 ( >7. 



§E. W. Hilgard, On the Geology of Lower Louisiana, Smithson. 

 Contrib. to Knowledge, no. 248, — 1872; pp. 3 and 4. 



II J. D. Dana, Manual of Geology, 2nd ed. , — 1875; pp. 547-8. 



