150 Scientific Intelligence. 



plates i-xi, figures ]-54, and 6 geological maps), contains 

 detailed reports upon the geology of counties of Allamakee, Linn, 

 Van Buren, Keokuk, Mahaska and Montgomery, written by sev- 

 eral members of the geological corps. 



9. Illinois State Museum of Natural History. — Bulletin No. 6. 

 Description of New Species of Paleozoic Echinodermata, by 8. A. 

 Miller and Wm. F. E. Gurley, pp. 1-62, plates i-v. Spring- 

 field, 111., April, 1895. 



10. Geological Survey of Canada. — The second part of the 

 third volume of "Paleozoic Fossils" was published September, 

 1895 (pp. 45-128, plates ix-xv), and contains the following 

 papers by J. F. Whiteaves, viz : 2. Revision of the fauna of the 

 Guelph formation of Ontario, with descriptions of a few new spe- 

 cies. 3. Systematic list, with references, of the fossils of the 

 Hudson River or Cincinnati formation of Stony Mountain, Mani- 

 toba. 



11. A needed Term in Petrography, by L. V. Pirsson. (Ab- 

 stract of paper read at the winter meeting of Geological Society of 

 America.) — The term crystal when properly used carries with it 

 essentially the idea of an outward geometric form bounded by 

 planes arranged according to certain laws of symmetry, though it 

 implies also a certain interior molecular structure with definite 

 physical properties. There is thus at present no good term to 

 express the formless or rounded masses in which minerals occur, 

 especially in eruptive rocks, and which possess the interior molecu- 

 lar structure of crystals though not their outward form. For 

 such formless or rounded masses the term anhedron (without 

 planes) is proposed, and such mineral masses may also be spoken 

 of as having an anhedral development. 



12. Manual of Lithology, by E. H. Williams, 2d ed., revised 

 and enlarged, 8°, 418 pp., 6 plates. New York, 1895 (Wiley Pub.). 

 — In this new edition of his little manual Prof. Williams has so 

 greatly enlarged and in so many details changed the character of 

 the work that it bears little resemblance to the former edition. 

 After a short introduction and discussion, the chief rock-makiug 

 minerals are described ; then follows an explanation of the terms 

 (of structure, etc.) used in lithology, which is succeeded by the 

 description of the different kinds of rocks, which comprises all 

 three groups, the igneous, sedimentary and metamorphic. The 

 volume closes with a scheme for determining rocks by their mega- 

 scopic character combined with physical and chemical tests. 



In the brief limits of this notice it is impossible to give any 

 extended review of the work. We note, however, that the pro- 

 posed basis of classification for the igneous rocks, based as it is 

 on the predominance of the ferro-magnesian silicate present, must 

 present so many uncertainties, together with some absolute con- 

 tradictions, that it is scarcely probable that it will be generally 

 adopted. We notice also in places obscurities in the author's 

 style which render it difficult to ascertain his precise meaning. 



l. v. p. 



