Geology. 475 



given hy him to the Institute in 1893. The other papers of the 

 volume are entitled : Some Principles Controlling the Deposition 

 of Ores, by C. R. Van Hise ; The Secondary Enrichment of Ore 

 Deposits, by S. F. Emmons ; The Enrichment of Gold and Silver 

 Veins, by W. Lindgren ; Problems in the Geology of Ore 

 Deposits, by J. H. L. Vogt ; the Role of Igneous Rocks in the 

 Formation of Veins, by J. F. Kemp ; The Caliche of Southern 

 Arizona, by W. P. Blake ; The Character and Genesis of Certain 

 Contact Deposits, by W. Lindgren ; The Formation of Bonanzas 

 in the Upper Portion of Gold Veins, by T. A. Rickard. Many of 

 these papers have grown out of the discussion of Prof. Van Hise's 

 original and valuable contribution. The different writers, with 

 one exception, agree with him in his main conclusions. Prof. 

 Van Hise has contributed a concluding chapter in which the 

 chief points of the discussion are reviewed and summarized. A 

 valuable appendix to the volume gives an index of all the papers 

 on ore deposits which the Institute has published. w. e. f. > y 



6. Coal in Michigan, its mode of occurrence and quality • by 

 Alfred C. Lane, State Geologist, constituting vol. viii, pt. ii, 

 Geol. Survey of Michigan. Pp. 232, 9 plates and 9 figures. 1902. 

 — The author discusses the origin, occurrence, analyses and tests, 

 erosion and disturbance and development of Michigan coal. As 

 to the geological horizon of the coal seams he makes the follow- 

 ing statement, based upon paleontological analyses made by 

 Messrs. Girty and David White of the U. S. Geological Survey, 

 viz : "All the indications are that all our series are low down in 

 the Coal Measures (Mesocarboniferous), in fact in that section of 

 it known as the Pottsville formation, ' serai conglomerate ' or 

 * millstone grit' a part of the series which was once supposed, to 

 be below any important coal seams, though it is now known that 

 some of the best coals of the United States, the Lykens Valley of 

 Penn., the Pocahontas and New River of West Va., the Sharon 

 Marsillon and Mercer Coals of Ohio, belong to this series (p. 41). 



h. s. w. 



7. Adephagous and Clavicom Coleoptera from the Tertiary 

 Deposits at Florissant, Colorado ; by Samuel H. Sc udder. U. S. 

 G. S. Monograph XL, 148 pp., 11 pi., 1900. — This is a second 

 instalment toward the history of fossil coleoptera, the first of 

 which w T as published in 1893 as Monograph XXI, and contains 

 an account of the non-rhynchophorous coleoptera of North 

 America, 210 species of which are now known belonging to 26 

 families and 125 genera. The beautiful plates illustrate the new 

 species ; and in their proper places all the species of each genus 

 are recorded, thus giving a summary of present knowledge of the 

 extinct forms of the groups considered. h. s. w. 



8. Acrothyra and Hyolithes — a Comparison ; Hyolithes gra- 

 cilis and related forms from the Lower Cambrian of the /St. 

 John Group ; A backward step in Paleobotany; by G. F. 

 Matthew. Trans. Roy. Soc. Can., vol. vi, section iv, pp. 93-122. 

 — Dr. Matthew believes that the Pteropoda and the Brachiopoda 



