476 JRevieics — Geology of Maryland. 



Islands with the continent as proved by the old Admiralty Charts, and 

 the personal knowledge of the coasts gathered by Samuel Woodward, 

 of Norwich, from the fishermen of the North Sea and the captains of 

 ships along the coast. But there is much concerning this subject 

 which has been added to our knowledge in the past 100 years, and 

 such maps as are now produced were unknown in those days. Thus, 

 in the little map published by De la Beche [Researches in Theoretical 

 Geology, 1834, p. 190), he showed that "if the British Islands were 

 elevated one hundred fathoms above the level of the ocean, and thus 

 joined to the continent of Europe, they would be surrounded by an 

 extensive area of flat land"; but he then stated (p. 189) that "the 

 soundings round coasts present us with no lines which we might 

 consider to be those of valleys". jj w 



II. — Maryland Geological Sue vet, 



WE have received a copy of vol. ix, dated 1911, of the general 

 reports of this Survey, comprising the third and fourth (final) 

 and summary final reports on State Highway Construction. During 

 a period of twelve years the total road expenditures under the 

 auspices of the State Geological Survey have amounted to more than 

 one and three-quarter million dollars : the work is now carried on 

 under the State Roads Commission. The same volume contains 

 a "Report on the Iron Ores of Maryland", by Mr. J. T. Singewald, 

 jun. The ores consist of magnetite, hematite, limonite (including 

 bog iron ores), and siderite ; and the author describes their geological 

 position, extent, and origin. He also gives a history of the Maryland 

 iron industry, with descriptions of the various iron works. The 

 report is well illustrated with maps and photographic views. 



Another volume, of 622 pages with 97 plates and 15 text- 

 illustrations, is entitled "Lower Cretaceous", being the fourth of 

 a series dealing with the systematic geology and palaeontology of 

 Maryland. The preceding volumes were on the Tertiary and 

 Quaternary deposits. In the present great work the main geological 

 and palaeontological features of the Lower Cretaceous are described 

 by Dr. W. Bullock Clark (State Geologist), Mr. A. B. Bibbins, and 

 Mr. E. W. Berry. The system consists of the Potomac Group, 

 which is divided (in ascending order) into the Patuxent, Arundel, 

 and Patapsco Eormations. Mr. Berry contributes an account of the 

 Lower Cretaceous Floras of the World and of the Correlation of tlie 

 Potomac Eormations ; he also describes the many species of Maryland 

 fossil plants. The fossil vertebrata are dealt with by Mr. R. S. Lull, 

 and the mollusca, which include only Bythinia, Viviparus, Cyrena, 

 and ZTyiio, are described by Dr. Clark. 



We have further received a memoir on "The Physical Features 

 of Prince George's County ", in which the physiography, geology, 

 mineral resources, soils, climate, hydrography, and forests are 

 described. The rocks include small areas of crystalline rocks, gneiss, 

 serpentine, gabbro, and diorite, possibly of Archeean age. The main 

 areas are of Cretaceous, Eocene, Miocene, Pliocene (?), and later 

 deposits. Good illustrations are given of characteristic fossils, and 

 there are instructive views of scenery and geological formations. 



