90 BIBLIOGRAPHY OF NORTH AMERICAN GEOLOGY, [bull. 203. 
820 Whiteaves (J. F.). Note on a supposed new species of Lytoceras 
from the Cretaceous rocks at Denman Island in the Strait 
of Georgia [Canada]. 
Ottawa Nat, vol. 15, pp. 31-32, 1901. 
821 Whitehead (Cabell), Chatard (T. M.), and. An examination of 
the ores of the Republic Mine, Washington. 
See Chatard (T. M.) and Whitehead (0.), 125. 
822 Whitfield (R. P.) assisted by Hovey (E. O.). Catalogue of the 
types and figured specimens in the paleontological collec- 
tion of the geological department, American Museum of 
Natural History; Lower Carboniferous to Pleistocene 
inclusive. 
Am. Mus. Nat. Hist., Bull., vol. 11, pt. 4, pp. 357-500, 1901. 
823 Whitfield (R. P.). Note on a very fine example of Helicoceras 
stevensoni preserving the outer chamber. 
Am. Mus. Nat. Hist., Bull., vol. 14, p. 219, pi. 30, 1901. 
S24 Wieland (G. R.). A study of some American fossil Cycads. 
Part IV. On the microsporangiate fructification of Cyca- 
deoidea. 
Am. Jour. Sci., 1th ser., vol. 11, pp. 423-436, tigs. 1-3, 1901. 
Continues the description of the author's studies of the fructification 
of Cycadeoidca, which appeared in the American Journal of Science 
f..r March, L899. 
825 Williams (E. H., jr.). The alleged Parker channel. [Pennsyl- 
vania. J 
Geol. Soc. Am., Bull., vol. 12, p. 463, 1901. 
Describes abandoned channel of Allegheny Kiver. 
826 Williams (Henry Shaler). The discrimination of time values in 
geology. 
Jour. Geol., vol. 9, pp. 570-585, 1901. 
Discusses the criteria upon which the classification of strata should 
depend and proposes a plan of a biochronic classification and nomencla- 
ture. 
827 Points involved in the Siluro-Devonian boundary question. 
Abstract: Geol. Soc. Am., Bull., vol. 12, pp. 472-473, 1901. 
Gives brief summary of questions in dispute. 
828 [Reviews of "The Eocene deposits of Maryland" and "Sys- 
tematic paleontology;" "Annual Report of the Geological 
Survey of Arkansas, 1892, Vol. V;" " Summary report on 
the operations of the Geological Survey of Canada" by 
G. M. Dawson; and "A revision of the genera and species 
of Canadian Paleozoic Corals — The Madreporaria aporosa 
and the Madreporaria rugosa" by L. M. Lambe.] 
Am. Jour. Sci., 4th ser., vol. 12, pp. 77-80, 1901. 
