492 



SCIENCE. 



[N. S. Vol. II. No. 41. 



Silurian strata of the Lake Superior region and 

 eastern New Yorlv (including adjacent areas in 

 Canada and New England). This similarity is 

 expressed in the lithological structural and 

 faunal character of the rocks of the two regions. 

 Strata of the Lower, Middle and Upper Cam- 

 hrian are recognized in both districts. A plea 

 is made for the use of lithological constants in 

 correlating rocks belonging to the earlier 

 epochs of geological history when similar 

 oceanic and physical conditions spread over 

 vast expanses of the earth's surface. 



Braceiocrinus and Herpetocrinus: By F. A. 

 Bather. The generic terms Brachiocrinus and 

 Myelodactyhts were early applied to so-called 

 arm fragments of crinoids. These seem to 

 have been really stem fragments, and as such 

 were later correctly described as Herpetocrinus, 

 which term the author thinks wise to retain in 

 place of the others. A revised diagnosis of 

 H. nodosarius is presented. 



Description of a New Genus and Five New 

 Species of Fossils from the Devonian and Sub- 

 Carboniferous Bocks of Missouri: By R. R. 

 Rowley. The new genus is Aristocrinus, and 

 the new species belong to the genera Allagec- 

 riiius, Granatocrinns, Goniatites; Pleurotomaria 

 and Murch'isonia. 



The Elective System as Adopted in the Michigan 

 Mining School : By M. E. "Wadswoeth. The 

 Michigan Mining School has recently adopted 

 an elective system which allows more freedom 

 of choice than that in any other mining or 

 technical school. Two studies only — elemen- 

 tary geology and the elementary principles of 

 mining — are required of all students, but there 

 is in some cases a natural sequence of studies, 

 so that students, in order to pursue advanced 

 work in certain lines, must fir.st complete the 

 earlier work in the sequence. 



Bock Sill, Long Island, N. Y.: By John 

 Bkyson. An immense boulder on the summit 

 of Rock Hill is described and figured. This 

 boulder is now about 50 by 20 feet, but the au- 

 thor thinks that it was originally, before being 

 quarried for stone, more than 125 by 20 feet. 

 Several other glacial features of the region are 

 discussed. 



The Geological Society and American Associa- 

 tion Meetings : By Warren Upham. An ex- 



tended and complete account of the recent 

 meetings at Springfield, Mass., is given. Ab- 

 stracts of all the papers (and discussions) 

 read before the Geological Society and before 

 Section E of the A. A. A. S. are included. 



The International Geological Congress. — A Cor- 

 rection : By Albert Heim. Prof. Heim calls 

 attention to some misstatements concerning 

 himself which appeared in the account of the 

 last meeting of the Congress. 



JSTEW BOOKS. 



The Manufacture of Explosives. OscAR Gutt- 

 MANN. 2 Volumes. New York, Macmillan 

 & Co. London, Whittaker & Co. 1895. 

 Pp. xiii+348, xii-|-444. .$9.00. 



Solution and Electrolysis. W. C. D. Whetham. 

 Cambridge University Press. New York, 

 Macmillan & Co. 1895. Pp. viii + 296. 

 $1.90. 



A Laboratory Manual of Organic Chemistry. Dr. 

 Lassar-Cohn. Translated by Alexander 

 Smith. London and New York, Macmillan 

 & Co. Pp. xix-F403. S2.25. 



Bulletins of the U. S. Geological Survey, No. US. 

 Pp. vi-|-131. A Geographic Dictionary of New 

 Jersey. Henry Gannett. No. 119. A Geo- 

 logical Beconnoissance in Northwest Wyoming. 

 George Homans Eldridge. Pp. vi-!-72. 

 No. 120. The Devonian System of Eastern 

 Pennsylvania and Ne^v York. Charles S. 

 Prosser. Pp. vi + 81. No. 121. A Bibli- 

 ography of North American Paleontology. 

 Charles RoLLiN Keyes. Pp. vi+251. No. 

 122. Be.wlts of Primary Triangulation. 

 Henry Gannett. Pp. vi-|-412. Govern- 

 ment Printing Office, Washington, D. C. 

 1894. 



Lakes of North America. ISRAEL C. Russell. 

 Boston and London, Ginn & Co. 1895. Pp. 

 x+125. $1.65. 



Greenhouse and Windotv Plants. Charles Col- 

 lins. London and New York, Macmillan & 

 Co. 1895. Pp. x + 160. 40cts. 



The Production of Coal in 1S94. Edw.^RD 

 Wheeler Parker. From the Sixteenth 

 Annual Report of the Director of the U. S. 

 Geological Survey, Washington, 1895. Pp. 

 224. 



