548 REVIEWS 



important in the present connection, though Medina shales are used in Ontario in the 

 manufacture of pressed brick, while vitrified brick are made from Salina shales at War- 

 ners, Onondaga county, N. Y. Hamilton shales are utilized at Cairo, Greene county, 

 in the manufacture of paving brick ; and at Jewettville, Erie county, for pressed brick 

 manufacture. Sewer pipe, drain tile and terra cotta are made from Portage shales at 

 Angola, Erie county. Chemung shales are utilized at Jamestown, Chautauqua county; 

 Alfred, Allegany county; Hornellsville, and Corning, Steuben county; and Horse- 

 heads, Chemung county. 



Feldspar and quartz are obtained from large pegmatite veins occurring near Bed- 

 ford, Westchester county, and are shipped to the potteries at Trenton, N. J. 



Report on Louisiana Clay Samples. Geological Survey of Louisiana, 

 Report for 1899. Pp. 263-275. 



Discussion of origin, composition and properties of clay, followed by reports on 

 physical tests of six samples of clay. All of the clays tested could be used in the manu- 

 facture of pressed brick, while one could also be used for paving brick and two for 

 earthenware. 



Clay and its Manufacture into Brick and Tile. Mineral Industry, Vol. 

 IX, pp. 93-135, 12 figures, 1901. 



Detailed discussion of the manufacture of building and paving brick, roofing and 

 floor tile, terra cotta and sewer pipe. 



Report on the Clays of Marylarid. Special Publication, Vol. IV, Pt. Ill, 

 Maryland Geological Survey. 8vo, pp. 203-507; Pis. XIX-LXIX, 

 including six geologic maps; Figs. 5-34, 1902. 



A general discussion of the origin, properties, uses and technology of clays is fol- 

 lowed by detailed descriptions of the Maryland clays, and a resume of the industries 

 based on them. 



According to Shattuck, the Pleistocene of Maryland is divisible into three forma- 

 tions ; the Talbot, Wicomico, and Sunderland. The newest of these, the Talbot, 

 does not exceed forty-five feet in thickness ; and often carries lenses of greenish-black 

 clay. The Wicomico, which is from forty-five to one hundred feet thick, seldom con- 

 tains clay deposits of economic value. The Sunderland contains clay beds which are 

 well shown in Calvert and St. Mary's counties. None of the Pleistocene clays are used 

 for anything except common brick, though occasionally clays occur fit for tile or 

 terra cotta. 



The Neocene is represented by the Lafayette and Chesapeake formations. The 

 Lafayette consists of gravels, sands and clays, very irregularly stratified, and changing 

 character rapidly along the deposition planes. The Chesapeake consists chiefly of 

 sands of marls with only local developments of clay. 



Clark and Martin divide the Maryland Eocene as follows : 



GROUP. FORMATION. MEMBER. 



f ,, . C Woodstock 



I Nan J em °y Potapaco. 



Pamunkey \ C Paspotansa 



t A( l Ula •" \ Piscataway. 



Of these four members only one, the Potapaco, contains clay deposits of impor- 

 tance. The Potapaco consists of argillaceous (and often gypseous) green sand, with a 



