Geology. 237 



66th Congress, 74 pp., 6 figs., 1919.— This interesting report 

 describes in detail the earthquake of 1918, the distribution of the 

 apparent intensity, the secondary phenomena, effects on struc- 

 tures, after shocks, etc. The earthquakes in the Virgin Islands in 

 1867-1868 are also described, and there is a catalogue of 275 

 shocks in Porto Rico and the Virgin Islands from 1772 to 1918. 



c. s. 



3. Scientific Survey of Porto Rico and the Virgin Islands. 

 Vol. I, Part 1. Published by the New York Academy of Sciences, 

 110 pp., 4 pis., 26 text figs., 1 map, 1919.— This is the first of the 

 final reports of a scientific survey. of Porto Rico made through 

 the cooperation of the New York Academy of Sciences, Mr. Emer- 

 son McMillin, and the Porto Rico government. The report opens 

 with a history of the survey by N. L. Bbitton (10 pages), fol- 

 lowed by a "Geological Introduction" by C. P. Berkey (pp. 

 11-29), a "New Base Map of Porto Rico," by C. A. Reeds (pp. 

 30-31), and a detailed account of the geology of the San Juan 

 region, by D. R. Semmes (pp. 33-110). 



It is a most interesting report, describing the ' ' Older Series, ' ' 

 the core of a mountain chain of Cretaceous (probably also some 

 Comanchian) and early Eocene sediments, with much igneous 

 interbedded material of explosive volcanoes. Then followed 

 deformation and peneplanation, and later, submergence ,with the 

 deposition of the "Younger Series" of Cenozoic (chiefly Oligo- 

 cene) marine sediments, devoid of volcanics and laid down on 

 the flanks of the central Older Series. c. s. 



4. La Fauna Jurasica de Vinales; by Mario S. Roig. Cuba, 

 Secretaria de Agricultura, etc., Boletin Especial, 61 pp., 26 pis., 

 1920. — In this memoir are described and illustrated forty-three 

 forms of ammonites from the higher Jurassic of western Cuba. 

 Many are common to Cuba and southern Europe. c. s. 



5. Maryland Geological Survey. Cambrian and Ordovician; 

 by R. S. Bassler. Pp. 424, 58 pis., 277 text figs., 1919.— This 

 Cambrian-Ordovician memoir of the Maryland State Survey, like 

 all the other reports issued by that splendid organization, is a 

 work of great importance in American stratigraphy. As is well 

 known, the western extension of Maryland is very narrow but 

 long geographically, and if a thorough grasp of its Paleozoic 

 sequence is to be attained, its formations must be studied in the 

 light of their continuance in West Virginia and Pennsylvania. 

 This has been done, and the present report is therefore an account 

 of the Cambrian and Ordovician of those states as well as of Mary- 

 land. In addition, stratigraphic correlations are made with 

 many other areas of the United States. 



The Cambrian, Ozarkian, and Ordovician systems of Maryland 

 are here divided into 13 formations (7, 1, and 5 respectively), with 

 a total thickness of about 15,200 feet, of which more than 10,000 

 feet are limestones. The accompanying geologic map is small (1 

 inch == 5 miles), so that the formations described had to be 



Am. Jour. Sci. — Fourth Series, Vol. L. No. 297. — September, 1920. 

 17 



