REVIEWS 235 



(necessarily previous to the deposition of the Bradford schists), the 

 writer presumes an erosion interval between the very beds (Washington 

 limestone and the slate) which he classes together (see p. 78 and Plate 

 XIV). 



"The Geology of Grand Isle" is the subject of a chapter by Dr. 

 Perkins. This is the largest of the islands of Lake Champlain. The 

 term "Champlainian" is used instead of "Ordovician," and "Beekman- 

 town" instead of " Calciferous," upon grounds of priority. The much- 

 folded and tilted Utica shales, resting on only slightly disturbed Trenton 

 and Chazy beds, afford an excellent example of the different effects 

 which the same orogenic movements may have on strata of different 

 lithologic character and in different stratigraphic positions. 



Peculiar concretion-like organic remains in the Chazy are believed 

 to be sponges, and are placed by H. M. Seely in a new genus, Stepho- 

 chetus. Four new species of this genus are described and figured. A 

 petrographic description of the dikes of Grand Isle is given by H. W. 

 Shirmer, of Columbia University. 



The illustrations are numerous and especially good. 



E. S. B. 



Mi?ieral Resources of the United States. Calendar Year 1901. By 

 David T. Day. United States Geological Survey. 



The total value of our mineral production was $1,086,529,521 — a 

 gain of 2.15 per cent, over that of 1900. For the second time it was 

 more than a billion dollars. The twenty-two products whose value 

 exceeded a million dollars each are, in order of their value, as follows : 

 Coal, pig iron, copper, gold, silver (coining value), petroleum, stone 

 (building), natural gas, lead, cement, brick clay, zinc, mineral waters, 

 salt, phosphate rock, limestone (for iron flux), zinc white, clay (other 

 than brick), aluminum, gypsum, quicksilver, and pyrite. 



Coal. — The coal product of the United States for the year 1901 

 was the greatest in the history of the industry, its value being $348, - 

 910,464 — an increase of 14 per cent. The tonnage exceeded that of 

 Great Britain and colonies, and was 75 percent, greater than the output 

 of Germany. The industry gave employment to 485,544 men. There 

 were twenty-eight states and territories producing coal, and twenty- 

 two of them show increased output, the greatest per cent, increase being 

 that of North Dakota. Pennsylvania produced 51 per cent, of all the 

 coal mined. Illinois ranked second with 9.6 per cent. West Virginia, 

 Ohio, Alabama, Indiana, Kentucky, Colorado, and Iowa follow in 

 the order named. 



