Reviews — American Geological Surveys, Iowa. 221 



mineral kingdom ; but the two latter, as carbides and phosphides, 

 are of excessively rare occurrence. 



The only one mentioned under iron is the carburet, a name ap- 

 plied sometimes to plumbago or graphite, which is usually placed 

 by mineralogists in close proximity to the diamond as another 

 variety of carbon ; the iron being considered to be only mechanically 

 mixed with it, inasmuch as the iron occurs in variable quantities, 

 while the phosphides have only been found native in meteoric stones 

 in exceedingly small quantities ; the general occurrence being that 

 of a phosphate. 



Chapter 1st contains a table of the metals alphabetically arranged 

 with their symbols, equivalents, specific gravity, and date of dis- 

 covery. 



In the last Chapter is also given a classification of metals, based 

 on their relative affinity for oxygen, as also according to the nature 

 of their oxides, which is followed by a very brief account of their 

 mode of occurrence. 



The author has evidently a strong admiration for rhymes, but is 

 not always equally happy in the selections he has made ; take, for 

 instance, the following, signed " Eulalia Gurson," — but quite worthy 

 of Mr. Tupper, — on the metal Potassium, p. 85 : — 



" When thrown upon water, this metal ignites, 

 And leaps o'er its surface with violet-tinged lights ; 

 Or, if upon ice this substance you cast, 

 It will melt by degrees and be dissolved at last." 



There is a Grlossary of eight pages devoted to the explanation of 

 common words, to be met with in most dictionaries, but hardly 

 deserving the name it bears. 



II.— AMERICAN GEOLOGICAL SURVEYS. 



{Continued fi'om page 180.) 



Eepokt on the Geological Survey of the State of Iowa. By 

 C. A. White, M.D. Two vols. 8vo., 834: pages, and numerous 

 Lithographic Illustrations. (1871.) 



THESE are the results of observations made in the years 1866 — 

 1869, at an expense of 26,000 dols. for field-work, and of 

 18,000 dols. for publication. Iowa bad previously issued two octavo 

 reports in 1859, under the superintendence of Prof. James Hall, 

 LL.D., of Albany, N.Y., which described exclusively the geological 

 features of the eastern portion of the State, including the sketch 

 of the Mineral Eegion near Dubique, b}^ Prof. J. D. Whitney. Dr. 

 White's reports relate chiefly to the fields not explored by Professor 

 Hall. The earlier volumes describe the fossils so far as they were 

 known ten years ago. The later ones contain no palceontological 

 descriptions, although thei'e exists in private hands an immense 

 amount of material, chiefly the Mountain Limestone Crinoids from 

 the vicinity of Burlington. 



