94 BIBLIOGRAPHY AND INDEX OF N. A. GEOLOGY, [bull. 162. 
823 Upham (Warren). Fluctuations of North American glaciation 
shown by interglacial soils and fossiliferous deposits. 
Abstracts: Am. Assoc. Adv. Sci., Proc, -vol. xlvii, p. 297 (| p.); Am. 
Geol., vol. xxii, p. 258 (£ p.), 1898. 
824 Time of erosion of the Upper Mississippi, Minnesota, and St. 
Croix valleys. 
Abstracts: Am. Assoc. Adv. Sci., Proc, vol. xlvii, pp. 297-298 ($ p.); 
Science, new ser., vol. viii, p. 470 (± p.); Am. Geol., vol. xxii, pp. 258- 
259 (i p.), 1898. 
V. 
825 Van Diest (E. 0. and P. H.). Notes on the geology of the west- 
ern slope of the Sangre de Gristo Eange in Oostillo County, 
Colorado. 
Colo. Sci. Soc, Proc, vol. v, pp. 76-80, 2 figs., 1898. 
See Bibliography and Index for 1896, No. 689. 
826 Van Hise (C. E.). Metamorphism of rocks and rock flowage. 
Geol. Soc. Am., Bull., vol. ix, pp. 269-328, pi. 19, 2 figs. ; Abstract, 
Am. Jour. Sci., 4th ser., vol. vi, pp. 75-91; Review, Am. Geol., vol. xxii, 
378-379,1898. 
Describes the physico-chemical principles operative in the alteration 
of rocks and their application to the changes in the earth's crust, and 
the general character of the molecular dynamic action and mass 
dynamic action accompanying it. 
827 Estimates and causes of crustal shortening. 
Jour, of Geol., vol. vi, pp. 10-64, 11 figs., 1898. 
Discusses the evidences for the shortening of the earth crust and the 
causes which account for such phenomena. 
828 The volume relations of original and secondary minerals in 
rocks. 
Abstracts : Science, new ser., vol. viii, p. 465 (61.); Am. Geol., vol. xxii, 
p. 252 (5 1.), 1898. 
829 See Diller (J. S.), No. 234. 
830 Van Ornum (Mr.). [Geology and its relations to topography.] 
Am. Soc. Civil Engrs., Trans., vol. xxxix, pp. 90-92, 1898. 
In discussion of paper by John C. Branner on the same subject. 
831 Vaughan (T. Wayland). [Fossil corals collected by R. T. Hill in 
Costa Rica.] 
Harvard Coll., Mus. Comp. Zool., Bull., vol. xxviii, p. 275 (£ p.), 1898. 
Names the species determined. 
832 and Hill (R. T.). The Lower Cretaceous Gryphoeas of the 
Texas region. 
See Hill (R. T.), and Vaughan (T. W.), No. 356. 
