IV BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Page 

 Chief features of the stratigraphy and structure of mount Diablo, 



California [abstract] ; by Geoege D. Louderback 527 



Grenville-Hastings unconformity [abstract] ; by Willet G. Miller 



and Cyril W. Knight 539 



New Upper Siluric fauna from southern Michigan ; by W. H. 



Sherzeb and A. W. Grabau 540 



Nomenclature and subdivision of the Upper Siluric strata of Mich- 

 igan, Ohio, and western New York [abstract] ; by A. C. Lane, 



Charles S. Peossee, W. H. Sherzeb, and A. W. Gbabau 553 



Structure and stratigraphy of the Ouachita Ordivician area, Ar- 

 kansas [abstract] ; by A. H. Purdue 556 



Session of Tuesday, December 31 557 



Notes on the Crazy mountains, Montana [abstract] ; by John E. 



Wolff 557 



Glaciation in the Crazy mountains of Montana ; by George Rogers 



Mansfield 558 



Discovery of fish remains in Ordovician of the Black hills. South 



Dakota [abstract] ; by N. H. Darton 567 



Benitoite: its mineralogy, paragenesis, and geological occurrence 



[abstract] ; by George D. Louderback and W. C. Blasdale 569 



Geologic processes and geographic products of the arid region ; by 



Charles R. Keyes 570 



Committee on geological nomenclature 576 



Register of the Albuquerque meeting, 1907 578 



Session of the Cordilleran Section, Tuesday, December 31, 1907 578 



Accessions to the library from October 1, 1907, to September 30, 1908 579 



List of Officers and Fellows of the Geological Society of America 589 



Index to volume 19 601 



ILLUSTRATIONS 



Plates 



Plate 1 — Sardeson : Map of the Mississippi river from Minneapolis to Fort 



Snelliug 37 



2 " Sections at Fort Suelling 39 



3 — Ceoss : Wind erosion in the plateau country 57 



4 " Wind erosion in the plateau country 58 



5 — ^Keyes : Gypsum sand dunes 84 



6 — Woodman : Astropolitlion hindi 103 



7 " Specimens of slate and concretions 104 



8 " Contact of Meguma and Lower Carboniferous, Gays 

 River gold mine 107 



9 — Arnold and Anderson : Stream conglomerate 148 



10 " " Stream conglomerate 152 



11 — Gushing: Geological map of the Theresa (New York) quad- 

 rangle 158 



12 — Patton : Structure of Utah rhyolite 181 



13 " Topaz crystals from Utah 184 



