Jakuaey 1, 1904.] 



SCIENCE. 



25 



a- question whieli is reserved for further study 

 and discussion. The Bradfordian faunas are 

 equally distinct from those of the Chemung 

 group, on one hand, and from those of the 

 Waverly group, on the other. They contain 

 to some extent ah intermingling of Carbon- 

 iferous and Devonian species, and are in fact 

 transitional between those of the two eras cor- 

 responding to the position of the rocks in 

 which they are found. 



A recent bidletin of the U. S. Geological 

 Survey, by Professor H. S. Williams, which 

 deals with the migrations of faunas, so far as 

 it involves the rocks and faunas under con- 

 sideration, is based upon a misconception of 

 their strafigraphic relations. 



• This was followed by a paper entitled 

 ' Fluorspar Deposits of Southern Illinois,' by 

 Dr. H. Foster Bain. 



These deposits occur within an elliptical 

 area about forty miles in diameter covering 

 positions of southern Dlinois and the adjacent 

 part of Kentucky, and forming a truncated 

 dome probably reduced to a peneplain in Ter- 

 tiary time. The region is one of the normal 

 faulting and the individual blocks of strata 

 are very irregularly disposed. The ore occurs 

 in fissure veins along these fault planes. In 

 the region are a number of dikes of mica- 

 peridotite, biotite-pyroxenite and diabase. The 

 type of deposits, unusual in the Mississippi 

 valley, associated with the igneous rocks sug- 

 gests a genetic relation and the analogy with 

 the fluorspar deposits of the northern England 

 is very close. 



The 148th regular and 11th annual meeting 

 of the society took place on December 10. 

 The first part of the meeting was occupied by 

 the presidential address of Dr. C. Willard 

 Hayes, entitled ' Should There be a Federal 

 Department of Mines.' Later the reports of 

 the secretaries and treasurers were presented 

 followed by the election of officers for the 

 ensuing year. 



President — C. Willard Hayes. 



Vice-Presidents — George P. Merrill and Walde- 

 mar Lindgren. 



Secretaries — Walter C. Mendenhall and Alfred 

 H. Brooks. 



Treasurer — George W. Store. 



Members of Council at Large — ^David White, 

 X. W. Stanton, T. Wayland Vaughan, M. R. Camp- 

 bell and Leslie F. Eansom. 



Alfred H. Brooks, 



Secretary. 



CHEMICAL SOCIETY OF AVASHINGTON. 



The 144th regular meeting of the Washing- 

 ton Chemical Society was held on October 8, 

 at 8 P.M., in the assembly hall of the Cosmos 

 Club. In the absence of the president, the 

 meeting was called to order by the vice-presi- 

 dent. Dr. E. T. Allen. 



The program for the evening consisted of 

 two papers. The first paper, entitled ' Second 

 Report on Cement Analysis,' was presented by 

 Dr. W. F. Hillebrand and dealt with the results 

 of the analyses of two samples of cement ma- 

 terial, which were made by nineteen chemists 

 working independently. The results obtained 

 by these chemists were compared with a stand- 

 ard analysis made by Dr. Hillebrand and many 

 of the determinations differed very markedly 

 from the standard results. A discussion of 

 these variations was entered into by the author, 

 and it was pointed out that, although many 

 differences existed among the determinations 

 made by the various analysts, it was not neces- 

 sary to assume that the source of the errors lay 

 with the method, but was due to other factors 

 which must be taken into consideration. 



The second paper on the program was pre- 

 sented by Dr. Atherton Seidell, and was en- 

 titled ' Precipitation of Zinc by Manganese 

 Peroxide, with especial reference to the Vol- 

 hard Method of Determining Manganese.' 

 The problem involved and the method used 

 for the analysis of the precipitate formed in 

 the Volhard method for the determination of 

 manganese were briefly described. The re- 

 sults of the investigation lead to the conclusion 

 that zinc is always carried down by the pre- 

 cipitated peroxide of manganese. The amount 

 found in the precipitate depends upon the 

 quantity which is present in the solution at 

 the time the precipitation is made. 



The ratio between the zinc oxide and the 

 manganese peroxide found in the precipitates 

 indicates the formation of mixtures having 

 definite molecular ratios. 



