Geology and Mineralogy. 149 



cates, the Cephalopoda of the Lower Ordovician are here 

 described. These number 71 species, of which 24 are new. One 

 new genus is also described — Orygoceras. Of these 71 species, 

 46 are restricted to the Beekmantown, the remainder to the 

 Chazy. In other words, not a single species is common to the 

 two formations. 



The derivation of these cephalopods seems in the main to have 

 been from the southwest, i. e., the Pacific-American region. 

 South Europe (Atlantic-Bohemian) and North Europe (Baltic) 

 appear to have furnished little, if anything. The author has 

 done his work well in a difficult subject, all the harder to unravel 

 because of the fragmentary nature of the material. c. s. 



6. Geology of the Penn Van-Hammondsport Quadrangles / 

 by D. D. Luther. Bull. 101, N. Y. State Museum, pp. 37-58, 

 two maps in pocket. — Describes and maps the areal distribution 

 of the fourteen formations of the Middle and Upper Devonian 

 occurring within these two quadrangles. 



7. A Monograph of the Carboniferous and Pernio- Carbon- 

 iferous Invertebrata of New South Wales. Vol. II. Peleeypoda. 

 Part I. The Palmopectens ; by E. Etheridge, Jr., and W. S. 

 Dtnsr. Mem. Geol. Surv. N. S. Wales, 1906, pp. 1-39, pis. 1-16. 

 — The aviculopectens of the Carboniferous of New South Wales 

 are rare, small, and closely allied to European and American 

 forms. Those of the Permo-Carboniferous marine beds are, 

 however, of large size, great variety, and limited to eastern Aus- 

 tralia. The species are of three genera : Avicidopecten (10 

 species), Deltopecten (9 species), and JEntolium avicidatum. 



c. s. 



8. Geology and Underground Waters of the Arkansas Val- 

 ley in Eastern Colorado ; by N. H. Darton. Pp. 90, pis. xxviii, 

 figs. 2. Professional Paper No. 52. U. S. Geol. Survey, Wash- 

 ington, D. C. 1906. — This report is similar in form to other pro- 

 fessional papers by the same author upon districts within the 

 Great Plains and Rocky Mountain provinces of the United 

 States. The areal geology is represented by large geological 

 maps and the descriptions supplemented by numerous well-chosen 

 photographs. One of the chief values of this report is in the 

 information which it gives to well-drillers as to the occurrence 

 and depth of the water-bearing strata, a matter of great import- 

 ance in the semi-arid region of eastern Colorado. j. b. 



9. The Geological History of Mount Greylock ; by T. Nel- 

 son Dale. Pp. 17, pi. 1, fig. 4. Berkshire Historical and Scien- 

 tific Society. 1906. — In this paper the author reviews in an 

 interesting and somewhat popular manner the periods in the his- 

 tory of Mount Greylock from the time of the Cambrian trans- 

 gression. J. B. 



10. A Treatise on Pocks, Pock-weathering and Soils/ by 

 George P. Merrill. Pp. xv + 400, pis. 31, figs. 42. New 

 York, 1906 (The Macmillan Company). — The geological public 

 is already familiar with this work which, since its first appear- 



