COMMUNICATtON DE M. WARREN UPRAM 
245 
PeRIODS AND EPOCHS OF OuATERNARY TIME. 
The Lafayette period. The broad lower part of the Mississipi 
'■alley, froin the Southern boundary of the glacial drift to Loiii- 
contains a verj extensive nnfossilifcrous deposit of sand 
and gravel, designated formerly from its prevailing ferruginons 
color as the Orange sand, latcr called hy Mac Gee the Appom- 
^Uox formation in its development on the Coastal plain of the 
Atlantic and Gnlf States, but recently namcd the Lafayette for- 
"aation from Lafayette connty in northern Mississippi, wherc it 
'^as carliest discriminated by Prof. E. W. Hilgard in 1855 and 
1^56. Tins formation was spread across the valley plain 50 to 
miles or more in width along an extent of 600 miles from 
months of the Missouri and Ohio rivers to the Gnlf of 
mxico, dnring the closing stage of the Tertiary era and the 
_ Sinning of the Onaternary, to each of which it bas been as- 
^^ÿ'ned. Mac Gee *, Chamberlin and Salisbnry hold that it is 
P^obably referable to the Pliocène period ; while Spencer Hil- 
SardSj E. A. Smith®, and olhers, as it seems to me preferably, 
'^^'isidcr il as the earliest of our Pleistocene formations. Its 
^orthern continuation beneath the glacial drift is rccognized by 
‘ ^bsbnry ‘ in western Illinois to a distance of a hundred miles 
'^arthward from the Missouri river and boundary of the drift, 
gravels believed by him to be probably of the saine forma- 
occur in the Wisconsin and Minnesota driftless area, while 
|*ortheastward he lias observed the Lalbyelte gravels in the 
. 'O valley in Southern Indiana about 150 miles from the Missis- 
'"'PPi- Mac Gee States that the Lafayette beds attain their maxi- 
thickness, which is 200 feet or more, in the région about 
lui ®ci., III, vol. XXXV, Feb., April, May and .Tune 1888 ; vol. XL, 
lO U. S. Geol. Survey, ïwolflliAn. Rep., for 1890-91, p. 347-521, with 
amples and 45 figures in the text. 
Sci Geol. Society of America, vol. 1, 1890, p. 469-480. Am. Jour. 
V’ PP vol. XLI, May 1891. 
Ijjg last cited. Geol. Survey of Arkansas, An. Rep. for 1889 (published 
\ h O’ T’he Geologij of Crowletfs Hidge, p. 224-248. 
8 Survey of Georgia, First An. Rep. for 1890-91, p. 62. 
**^®'-* ’ volume 
. “b Nov. 1869 ; III, vol. II, Dec. 1871 ; vol. XLIII, May 1892. Am. Geolo- 
u> Vol, VIII, Aug. 1891, p. 129-131. 
, p Jour. Scii, 111, vol. XLVII, April 1894. 
•Jullcti 
in, Geol. Society of America, vol. III, 1892, p. 183-186. 
