400 Scientific Intelligence. 



regulations for the making of the Geologic Atlas has been pro- 

 mulgated (pp. 21-28). A special appropriation of $60,000 made 

 it possible to send five field parties into Alaska and the expansion 

 of the work led the Secretary of the Interior to create a Division 

 of Alaskan Mineral Resources in charge of Mr. A. H. Brooks. 

 The section of Physics is conducting experiments upon the 

 behavior of rock-forming minerals and upon the force exerted by 

 growing crystals. Plans have been completed by Dr. A. L. Day 

 and equipment provided for enlarging the scope of this work. 

 The hydrographic work of the United States has reached enor- 

 mous proportions since the law regarding the reclamation of arid 

 lands was passed. Four divisions now constitute the hydro- 

 graphic branch — hydrography, hydrology, hydro-economics and 

 reclamation service ; and the funds available for this work and 

 not included in the appropriation for the Geological Survey 

 amount to over $3,000,000 annually. The Survey has more than 

 ever the confidence of the scientific and business world. 



Monograph No. XL VI. The Menominee Iron-Bearing Dis- 

 trict of Michigan ; by William Shirley Bayley. 513 pp., 43 

 pis., 54 figs. — This is the sixth and the last of the series of mono- 

 graphs to be published, dealing with the separate iron-bearing 

 districts of the Lake Superior region. Another volume devoted 

 to the general geology of the Lake Superior region as a whole is 

 to follow. 



The Menominee district forms a narrow tongue with an area 

 of 112 square miles on the Michigan side of the Menominee River. 

 It has been an important factor in the iron ore production since 

 1877. The district is bordered by areas of Archean schists and 

 granites. The Huronian sediments of the district, in which occur 

 the ore bodies, lie in a trough between these older rocks. Struc- 

 turally this trough is a synclinorium composed of several impor- 

 tant anticlines and synclines. The Huronian rocks are divided 

 into two series called the Upper and Lower Menominee, which 

 are separated from each other by an unconformity. The Lower 

 Menominee series comprises 1,050 to 1,250 feet of quartzites and 

 conglomerates with 1,000 to 1,500 feet of dolomites. The Upper 

 Menominee series comprises the Vulcan formation, 650 feet thick 

 and the Hanbury slate. The Vulcan formation includes three 

 members, the iron-bearing Traders member, consisting largely of 

 detrital ores and jaspilites, but having basal layers of slate, 

 quartzite and conglomerate ; the Brier member, composed of fer- 

 ruginous and siliceous slates and the Curry member, consisting of 

 quartzites, ferruginous quartzose slates, jaspilites and ores. 



The larger ore deposits all rest upon relatively impervious 

 foundations which are in such a position as to constitute pitching 

 troughs. The ores of this district, like those of the Gogebic and 

 Marquette districts, were concentrated by descending waters flow- 

 ing in definite channels and the general processes involved were 

 the same as those worked out by Van Hise for these other dis- 

 tricts. 



