LIST OF ILLUSTRATIONS. 



PLATES. 



Facing page 



1. View showing wall and rail cases and installation of nonmetallic minerals 



on gallery of southwest court, U. S. National Museum. Looking 

 west 155 



2. View showing rail case and installation of nonmetallic minerals in gallery 



of southwest court of U. S. National Museum. Looking north 1 55 



3. Views in graphite mine near Hague, Warren County, New York. From 



photographs by C. D. Walcott 170 



4. Section of the salt deposits at Stassfurt. From the Transactions of the 



Edinburgh Geological Society, V, 1884, p. 11 1 204 



5. Views of brine-evaporating tanks at Syracuse, New York. From photo- 



graphs by I. P. Bishop 210 



6. View of Tripoli mines in Carthage, Missouri 218 



7. Deposit of diatomaceous earth, Great Bend of Pitt River, Shasta County, 



California. From a photograph by J. S. Diller 219 



8. Map showing distribution of corundum and peridotite in the eastern 



United States. After J. V. Lewis, Bulletin II, North Carolina Geo- 

 logical Survey 222 



9. Microstructure of emery. After Tschermak, Mineralogische und Petro- 



graphische Mittheilungen XIV, Part 4 224 



10. Section showing the formation of manganese deposits from dec-ay of 



limestone. After Penrose, Annual Report Geological Survey of Arkan- 

 sas, I, 1890 252 



11. Botryoidal psilomelane, Crimora, Virginia. Specimen No. 66722, 



U.S.N.M 255 



12. Views showing occurrence Calcite in Iceland. After Thoroddsen 259 



13. View in a cement quarry near Whitehall, Ulster County, New York. 



From a photograph by N. H. Barton 268 



14. View in a soapstone quarry, Lafayette, Pennsylvania 319 



15. Microsections showing the appearance of (1) kaolinite and (2) washed 



kaolin 330 



16. Microsections showing the appearance of (1) halloysite and (2) ledaclay. 331 



17. Microsections showing the appearance of (1) Albany County, Wyoming, 



clay and (2) fuller's earth 332 



18. Leda clays, Lewiston, Maine. From a photograph by L. H. Merrill 333 



19. View in a Kaolin pit, Delaware County, Pennsylvania 339 



20. Map showing phosphate regions of Florida. After G. H. Eldridge 366 



21. Borax mine near Daggett, California. Interior and exterior views 398 



22. View of a gypsum quarry. From a photograph by the Iowa Geological 



Survey 408 



23. Peat beds overlying gold-bearing gravels, Mias, Russia. From a photo- 



graph by A. M. Miller , , 424 



163 



