Geology and Natural History. 331 



making in various lines, particularly with reference to safe- 

 guarding the lives of those engaged in mining and in insuring 

 economy in the development and use of fuels and other mineral 

 resources. For example, a series of investigations of explosions 

 has been carried on so that now the type of "permissible explo- 

 sives " in use has increased up to 13,000,000 lbs. in 1911. From 

 this and other related work conies the result that there has been, 

 in the past two years, a considerable reduction in the number of 

 lives lost in the coal mines in the country from explosions, 

 although the number is still far too large. Mine rescue work has 

 also been further developed ; the investigation of mines, as well 

 as laws and regulations for safety in mines, have made progress 

 in many States. Fuel investigations have brought much bene- 

 fit to the Government, as will be seen from the fact that the fuel 

 purchased under the advice of the Bureau in 1912 had. a value of 

 some $8,000,000. The amount of money expended by the Bureau 

 up to June 30, 1912, was nearly $476,000, of which $312,000 was 

 used for investigating mine accidents, $100,700 for testing fuels, 

 $7,200 for inspecting mines in the Territories, and the remainder 

 for general expenses, books, and publications. The total num- 

 ber of employees is 304. 



Recent publications (see vol. xxxiv, p. 405) include the fol- 

 lowing : 



Bulletins. — No. 43. Comparative fuel values of gasoline and. 

 denatured alcohol in internal-combustion Engines ; by R. M. 

 Strong and Lauson Stone. Pp. 243 ; 34 tables. 



No. 45. Sand available for filling mine workings in the 

 Northern Anthracite Coal Basin of Pennsylvania ; by N. H. 

 Darton. Pp. 33 ; 8 plates. 



No. 46. An investigation of explosion-proof Motors ; by H. H. 

 Clark. Pp. 44 ; 6 plates. 



No. 49. City smoke ordinances and smoke abatement ; by 

 S. B. Flagg. Pp. 55. 



Also Technical Papers, Nos. 25, 27, 28, 29, 32 ; Miners Circu- 

 lars, Nos. 9, 10, 11. 



3. Cambrian Brachiopoda ; by Charles D. Walcott. 

 Monog. LI, U. S. Geo!. Surv., 2 vols., text and. plates, pp. 872, 

 text figs. 76, pis. 104, 1912. — Dr. Walcoct has had this monu- 

 mental monograph on the Cambrian brachiopods of the world, his 

 magnum opus, in hand since 1898. In it are described 536 spe- 

 cies and varieties, grouped in 44 genera and 15 subgenera. Inci- 

 dentally 43 Ordovician forms are also defined. These 579 species 

 are illustrated by a great wealth of excellent photographs (re- 

 touched by Miss Wieser), of which there are upward of 4500. 

 Of these species 361 occur in North America, 132 in Europe, and 

 44 in Asia. In the Lower Cambrian there are 32 genera and 116 

 forms, showing clearly that the class Brachiopoda had its origin 

 far earlier in time ; it will not be surprising to find such as far 

 back as the Middle Proterozoic. The great bulk of Cambrian 

 brachiopods are inarticulate, phosphatic-shelled forms, and we 



