89 
539 Spurr (J. E.). The iron ores of the Mesabi range [Minnesota]. 
Am. Geol., vol. xiii, pp. 335-345. 
Abstract: Eng. and Mg. Jour., vol. lvii, pp. 583-584. 
Describes the structure of the rock formations, the character of the 
iron-bearing rocks and the changes they have undergone, and dis- 
cusses the origin of the ore deposits. 
540 The iron-bearing rocks of the Mesabi range, in Minnesota. 
Minn. Geol. and Nat. Hist. Surv., Bull., No. x, pp. viii-f-259, pis. i-xii. 
Abstract: Am. Geol., vol. xiv, pp. 251-252. 
Review : Jour, of Geol., vol. ii, pp. 545-546, by T. C. Hopkins. 
Describes the structure and stratigraphy of the range and the micro- 
scopic character of certain groups of the iron-bearing rocks. Dis- 
cusses the classification of these rocks and the nature of the agents 
that have affected them, and the formation, structure, and origin of 
the ore bodies. Includes a summary statement of the author's conclu- 
sions. 
541 Preliminary report on field work done in 1893. 
Minn. Geol. and Nat. Hist. Surv., 22d Ann. Rept,, pp. 115-124. 
Describes the area mapped and the topographic and geologic methods 
employed. Discusses the origin and age of the granite of Giants range 
and describes the schists and Thompson slates of the Keewatin series, 
the Cretaceous outliers, and the glacial phenomena. 
542 False bedding in stratified drift deposits. 
Am. Geol., vol. xiii, pp. 43-47, figs. 1-2. 
Describes the mode of formation of false bedding m a stratified drift 
deposit in northeastern Minnesota. 
543 Oscillation and single current ripple marks. 
Am. Geol., vol. xiii, pp. 201-206 (correspondence). 
Continues the discussion of the evidence of ripple marks described 
in No. 542. 
544 The stratigraphic position of the Thompson slates. 
Am. Jour. Sci., 3d ser., vol. xlviii, pp. 159-166. 
Describes the geograjdiic distribution of this series in eastern Min- 
nesota and their relations to the surrounding rocks. Reviews previous 
correlations, and discusses the evidences indicating their geologic age 
and their correlation with the Keewatin of the Mesabi range rather 
than with the Animikie. 
545 Stanton (Timothy W.). [On some Mesozoic and Tertiary exhibits 
at the World's Columbian Exposition.] 
Am. Geol., vol. xiii, pp. 289-290 (correspondence). 
Refers to the nomenclature of certain specimens from the Cretaceous 
and their geographic and stratigraphic occurrence. 
545« The Colorado formation and its invertebrate fauna. 
Review : Jour, of Geol., vol. ii, pp. 751-752, by H. F. Bain. 
Abstracts: Am. Nat., vol. xxviii, p. 510 (£ p.); Am. Geol., vol. xiv, 
P .51(;Lp.). 
Noticed in Bibliography and Index for 1892 and 1893. 
545fc Diller (J. S.) and. The Shasta-Chico series. 
Geol. Soc. Am., Bull., vol. v, pp. 435-464. 
See Diller (J. S.) and Stanton (T. W.), No. 155. 
