Geology and Mineralogy. 509 



thin-bedded limestones and sandstones). Within the Carbonifer- 

 ous area and often involved here in the igneous outflows are lim- 

 ited areas of SiluroDevonian and of Cambrian. The relations of 

 these strata to each other and to the igneous rocks are well shown 

 in the colored geological map, as also in the many excellent 

 sections. The discussion by Weed of these rocks and of the suc- 

 cessive orographic movements in which they have been involved 

 is highly interesting, but it is impossible to attempt to summarize 

 it here. The final chapter is devoted to the ore deposits and coal 

 of the region. 



3. Fossil Medusae ; by Charles D. Walcott. U. S. Geol. 

 Survey Monograph, vol. xxx, pp. 1-201, figs. 1-26, plates i-xlvii. 

 Washington, 1898. — Begiuning with the study of some obscure 

 siliceous nodules from the Coosa shales of Middle Cambrian age 

 from Alabama, Mr. Walcott has produced, in this monograph, an 

 example of the highest results of modern science in the interpre- 

 tation of fossil remains. It is sufficiently remarkable that any 

 reliable evidence of the existence of these jelly-like organisms 

 existed in Paleozoic time; but the description and illustration of 

 both the form and internal structure of fossil Cambrian Medusae 

 with some two hundred and fifty figures of specimens selected 

 from over 9000 examples could scarcely be imagined were it not a 

 fact. 



The Cambrian forms are referred by the author to a new 

 family, Brooksellidse, of the suborder Discomedusa?. The genus 

 Brooksella is represented by two species, and Laotira by one 

 species, all from the Middle Cambrian. The genus Dactyloidites 

 Hall, with one species, from the Lower Cambrian of New York, is 

 referred to the same family, Other Medusae, originally described 

 by Torrell and Linnarsson from the Lower Cambrian, are referred 

 to the genus Medusina, a name proposed to include all species of 

 fossil Medusa? whose generic characters cannot be determined. 

 Under the name Eopliyton, a number of markings, which have 

 been supposed by many writers to be remains of plains, are fig- 

 ured and their probable origin as trails of floating alga? or in some 

 cases of the tentacles of Medusa? is discussed. Descriptions and 

 figures of the known fossil Medusa? from the Jurassic and Per- 

 mian of Bohemia and Saxony are also given, and together with 

 the original description of the Coosa material form an important 

 monograph of the present knowledge of this group. The illustra- 

 tions are numerous both in text and plates and illustrate the sub- 

 ject with a fullness never before attained. h. s. w. 



4. The Cretaceous Foraminifera of yew Jersey ; by Kufus M. 

 Bagg, Jr. ; pp. 1-89, plates i-vi, U. S. Geol. Survey, Bulletin 88. 

 Washington, 189S. — This bulletin contains a description of over a 

 hundred species of foraminifera from the Matawan, Monmouth, 

 Rancocas and Manasquan formations of the Upper Cretaceous. 

 A Bibliography is appended. h. s. w. 



5. Some Lava-flows of the western slope of the Sierra Nevada^ 

 California ; by F. Leslie Bansome ; pp. 1-74, plates i-xi, U. S. 



