Hilgard on Drift in the Western and Southern States. 443 
this uplift, in a vertical fissure cutting through nearly horizontal 
rocks with a bearing, as described by Lesley, of 78° east 
north. It is filled with a sort of solidified bitumen, or asphalt, 
—the result, probably, of the slow oxydation of the heavy re- 
siduum of oils which once occupied it. 
Art. XLVI.—Remarks on the Drift of the Western and Southern 
Sales, and its relation to the Glacier and Iceberg Theories ; by 
Eve. W. Hitcarp, Pb.D., State Geologist of Mississippi. 
IN a recent paper on the Quaternary formations of Mississippi 
(this Journal, May, 1866), I have expressed my views concerning 
the remarkable formation designated as the “Orange Sand,” in 
my Report on the Geology of Mississippi. 
The admirable exposition of the whole subject of the Post- ’ 
tertiary formations in Dana's Manual of Geology, to which I have 
since been enabled to refer, as well as the portion of Dana’s Ad- 
dress before the American Association in 1855, relating to that 
period, Suggest to me with greater clearness the points to be set- 
tled in establishing the presumed correspondence of the Orange 
Sand of the Southwest to the recognized drift of the Northwest. 
On this subject I now propose to offer a few additional remarks, 
T have not perhaps, in the paper referred to, been sufficiently 
explicit, in comparing the Orange Sand to the northern drift in 
general, without specially mentioning as its supposed congener, 
the drift of the Northwest, particularly that of Illinois, Wiscon- 
sin, Iowa and Missouri. That the drift of New England, as de- 
scribed by Hitchcock and Dana, can be satisfactorily accounted 
for on the glacier theory alone, few who have delved among the 
ancient and modern moraines of Switzerland will question, 
ut the Western drift deposits, even so far north as Towa, as 
Hall's observations show, and still more in Iilinois and Missouri, 
differ seriously in their structure both from the New England 
moraines, and from the lines of blocks apparently left by the 
glacier melted zz situ. In the West the “erratic” blocks, both 
er een 
violently shoved forward by an unusual advance of the glacier, 
