324 NATURAL HISTORY BULLETIN. 



In addition to the references already given to Lyell's works, 

 there should be mentioned the several editions of his Prin- 

 ciples of Geology, beginning with the ninth, and of the Man- 

 ual of Elementary Geology following the third (?). In these 

 so far as noted (a few were not available) there are references 

 to land and freshwater shells, and to bones of mammals, in the 

 loess of the lower Mississippi valley, similar to those already 

 noted in the previous citations of Lyell's works. They are 

 evidently based on the same observations. 



The list of fossils quoted from Wailes' first report* is given 

 on p. 283 of that report. Another list appears on p. 339, in 

 which three species of the first list are wanting, namely: Helix 

 alternata, H. fratema, and //. tridentata, while three addi- 

 tional species are enumerated, namely: Helix pallia fa, H. say?] 

 and H. helieina. The first of these was found by both W. G. 

 Binney and the writer. The second, Helix (now Polygyrd) 

 say i is closely related to P. albilabris, and it is very probable 

 that large forms of the latter species were mistaken for it. 

 Like all the shells of Wailes' lists it is terrestrial, and belongs 

 to the modern southern fauna. Hence, even if the identifica- 

 tion was correct, it does not affect the status of the case. 

 Helix helieina of this list is Helieina orbiculata, a common 

 southern loess fossil. 



Another probable source of subsequently repeated errors is 

 Humphreys and Abbot's Report, f 



Speaking of the bluffs between Vicksburg and Baton Rouge 

 the authors say: "They are composed of loess, a post-pliocene 

 formation, similar to that of the Rhine .... That of Vicks- 

 burg .... is 300 feet high, and underlain near low-water 

 mark by a solid stratum of blue clay . . . Above the latter is 

 a stratum containing many marine shells and corals. Next 

 are deposits of yellow loam and sand containing vast numbers 



*See p. 306 of this Bulletin. 



t Report on the Physics and Hydraulics of the Mississippi River, by 

 Capt. A. A. Humphreys and Lieut. H. L. Abbot, no. 4, Professional 

 Papers of the Corps of Topographical Engineers, U. V S. Army, — 1861; 

 p. 95. 



