468 Scientific Intelligence. 



are described. The author's ideal has been "in treating each 

 great group of fossils, first to describe with some fulness a few 

 common species from which an idea of the general characters and 

 range of variation may be obtained; and then to give a brief 

 systematic account of the group." c. s. 



2. Cretaceous and Cenozoic Echinoidea of the Pacific Coast 

 of North America; by "William S. "W. Kew. Univ. California, 

 Bull. Dept. Geology, vol. 12, pp. 23-236, pis. 3-42, 5 text figs., 

 1920. — In this excellent work there are described and illustrated 

 90 forms (49 new) of echinids in 17 genera. Of these, 7 are 

 Mesozoic in time (2 in the Knoxville, 6 in the Chico), while the 

 great bulk, about 65, are found in the Miocene and Pliocene, 

 and only 4 in the Pleistocene. "In general," the author says, 

 "the echinoids are of limited range, as their evolution proceeds 

 rapidly. The species are easily recognized, the individuals are 

 often abundant, and their state of preservation is commonly 

 better than that of associated invertebrate forms. These factors 

 combined make the ,group of exceptional interest for biologic 

 studies, and of unusual importance in geologic correlation and 

 age determinations" (p. 26). The geologic time scale for the 

 Pacific coast opposite page 26 is very interesting and brings out 

 clearly no less than eleven unconformities since Jurassic time. 



c. s. 



3. Type Ammonites; by S. S. Buckman, with illustrations 

 from photographs mainly by J. W. Ttjtcher. — It is well to call 

 the attention of paleontologists to this periodic publication, as 

 it is of a fundamental character. No worker on ammonites can 

 be without it, not only to have the correct names for his fossils, 

 but even more to learn Buckman 's principles of classification. 

 The work is replete with new species and genera. There are 

 now published 23 parts, and the number of half-tone plates is 

 upward of 180. The work can be had of William Wesley and 

 Son, London. c. s. 



4. The American Species of Orthophragmina and Lepido- 

 cyclina; by Joseph A. Cushman. U. S. Geol. Survey, Prof. 

 Paper 125-D, pp. 39-108, pis. 7-35, 1 text fig., 1920.— The large 

 colonial orbitoid foraminifers are excellent horizon markers, as 

 the species attain to large size, have short geologic ranges, and 

 in addition are of wide geographic distribution. Here are 

 described 17 forms of Orthophragmina (2 new), the genus being 

 restricted to the Eocene; and 35 of the genus Lepidocyclina (13 

 new), which is restricted to the Eocene and Oligocene. The 

 latter are figured on 24 plates. The forms of the first-named 

 genus range in size up to 14 mm., while those of the latter attain 

 to 100 mm. or 4 inches. a s. 



5. Geology of the non-metallic mineral deposits other than 

 silicates. Vol. 1, Principles of salt deposition; by Amadeus W. 

 Grabau. Pp. xvi, 435, 125 text-figs., New York and London, 

 1920 (McGraw-Hill Book Company). — This well-balanced, exten- 



