Geology and Mineralogy. 75 



2. On Urnatella gracilis; by C. B. Davenport. Bulletin 

 Mus. Cornp. ZooL, vol. xxiv, No. 1, pp. 1-44, plates 1-6, 1893. — 

 This little known and aberrant Bryozoan has been made the sub- 

 ject of special study by Mr. Davenport. It was first noticed by 

 Leidy in 3 851, and later (1870 and 1884) further observations on 

 its anatomy and physiology were made by him. The anatomy 

 and non-sexual reproduction are now more fully described, and 

 the following important conclusions are reached : Urnatella is 

 closely related to Pedicellina. The Endoprocta are more primi- 

 tive than the Ectoprocta, as the latter pass through stages 

 resembling the adult condition of the former. The Endoprocta 

 bear only a superficial resemblance to Phoronis. The true 

 relationships of the Bryozoa are with the lowest worms, particu- 

 larly with the Rotifera. The Bryozoa and Rotifera, together 

 with the Mollusca, came from one phylum, and "after the Rotifer 

 stem had branched off, the common Mollusco-Bryozoan stem pro- 

 duced tentacles on the lateral ridges; that the two groups then 

 soon separated, the mollusca to undergo an extensive and com- 

 plicated development, the Bryozoa to remain at a low level." 



c. E. B. 



3. Lehrbuch der geologischen Formations- Kunde, fur Studir- 

 ende und zum Selbstunterricht, von Dr. Emanuel Kayser, 

 Prof. Univ. Marburg. 386 pp. 8vo, with many figures of sec- 

 tions and fossils. Stuttgart, 1891. (Ferdinand Enke.) — A 

 concise yet detailed account of the successive geological forma- 

 tions and their characteristic fossils. 



4. Mineral Resources of the United States — Calendar year 

 1891. David T. Dat. 630 pp. Washington: 1893.— This is 

 the ninth volume of the valuable series upon the Mineral Re- 

 sources of this country. Like its predecessors it contains a large 

 amount of useful information, compiled so as to be readily acces- 

 sible. The article upon aluminum is especially full, and we note 

 as of particular interest the statements made in regard to the 

 occurrence of bauxite in this country, in Alabama, Georgia and 

 Arkansas. As quoted from Prof. E. A. Smith, bauxite has been 

 mined in Alabama since November, 1891, and in the year follow- 

 ing some 3600 tons were shipped from Piedmont, while from Hermi- 

 tage, Georgia, about 1300 tons had been mined up to July, 1892. 

 The Alabama ore is stated to carry from fifty to sixty per cent 

 of alumina. It occurs associated with limonite and kaolins in 

 irregular beds, beneath the Knox dolomite of the Lower Silurian. 

 The best known occurrences are near Rock Run "Furnace in 

 Cherokee County, and it has also been discovered near Jackson- 

 ville in Calhoun County. J. W. Spencer, State Geologist, states 

 that the Georgia bauxite occurs in the residual clay from the 

 decomposition of the Knox dolomite in the belt commencing near 

 Adairsville and extending to the southwest. It occurs in pockets 

 often of great extent and is frequently associated with kaolin, 

 and at one locality with gibbsite. It is mainly in concretionary 

 nodules forming large masses or small kidney-shaped lumps 



