weeks.] PALEONTOLOGY, PETROLOGY, AND MINERALOGY, 1898. 91 
u. 
788 Udden ( Joiiaii August). Loess as a land deposit. 
Geo]. Soc. Am., Bull., vol. ix, pp. 6-9, 1898. 
Discusses the aqueous and teolian hypotheses of the origin of the 
loess. 
789 Fucoids or coprolites. 
Jour, of Geol., vol. vi, pp. 193-198, pis. vii-viii, 1898. 
Compares material found in the Devonian of the Mississippi Valley 
with Hall's description of Spirophyton and suggests a mechanical origin 
of these structures. 
790 A new well at Eock Island, 111. 
Am. Geol., vol. xxi, pp. 199-200, 1898. 
Gives the section of the well to a depth of 635 feet. 
791 Some preglacial soils. 
Iowa Acad. Sci., Proc, vol. v, pp. 102-104; Abstract, Am. Geol., vol. 
xxi, pp. 262-264, 1898. 
Describes the occurrence in Iowa and Illinois and gives a list of fos- 
sils collected. 
792 The mechanical composition of wind deposits. 
Augustaua Library Publications, No. 1, 69 pp., 1898. 
Discusses the character and mode of formation of wind deposits and 
its bearing on the problem of the loess. 
793 A geological romance. 
Pop. Sci. Mo., vol. liv, pp. 222-229, 7 figs., 1898. 
Describes the occurrence, character, and origin of the volcanic ash 
beds in Kansas. 
794 Uhler (P. R.). Preliminary notice of a recent series of geological 
accumulations — the McHenry formation. 
Md. Acad. Sci., Trans, pp. 395-400, 1898. 
Describes the occurrence, character, and flora of the formation on 
the western shore of Chesapeake Bay, in Maryland. 
795 Underwood (George C). See Day ( W. C.) No. 227. 
796 Upham (Warren). Niagara Gorge and Saint Davids Channel. 
Geol. Soc. Am., Bull., vol. ix, pp. 101-110, 1898; Abstract, Science, new 
ser., vol. vii, pp. 84-85, 1898. 
Describes the Niagara and Saint Davids gorges, the effect of the 
Laurentian glacial lakes on the gorge erosion, the epeirogenic move- 
ments of the region, and the duration of the falls and of the post-Glacial 
period. 
797 [Eeview of " Seventeenth Annual Eeport of the United States 
Geological Survey."] 
Am. Geol., vol. xxi, pp. 61-64, 1898. 
798 Shell-bearing drift on Moel Tryfair [Wales]. 
Am. Geol., vol. xxi, pp. 81-86, 1898. 
Compares this drift with that near Boston and in New Hampshire. 
