CONTENTS XI 



Page 

 Impressions made by bubbles, rain-drops, and other agencies; by W. H. 



TWENHOFEL 359 



Syngenetic origin of concretions in shale ; by W. A. Tarr 373 



Some conclusions in regard to the origin of gypsum; by F. A. Wilder 385 



On metamorphism in meteorites ; by G. P. Merrill 395 



Solitario uplift, Presidio-Brewster counties, Texas; by Sidney Powers... 417 

 Increased oceanic salinity as one cause of increased climatic contrasts ; 



by S. S. Visher 429 



Sweet Grass Hills, Montana ; by J. F. Kemp and P. Billingsley 437 



ILLUSTRATIONS 



Plates 



Page 



Plate 1 — Branner: Portrait of Joaquim Candido da Costa Sena 16 



" 2 — Merrill : Photomicrographs of meteorites 415 



" 3 " Photomicrographs of meteorites 415 



" 4 " Photomicrographs of meteorites 415 



" 5 " Photomicrographs of meteorites 416 



" 6 " Photomicrographs of meteorites 416 



" 7 — Kemp and Billingsley : West Butte, Sweet Grass Hills, Mon- 

 tana 445 



" West Butte, Sweet Grass Hills, Mon- 

 tana 446 



" Middle and Gold Buttes, Sweet Grass 



Hills, Montana 447 



10 " " Gold Butte, Sweet Grass Hills, Mon- 

 tana 448 



11 " " Dikes in the Sweet Grass Hills, Mon- 

 tana 450 



12 " " Diorite-porphyry dike and view of 



East Butte, Sweet Grass Hills, Mon- 

 tana ; 451 



Figures 

 Spencer : 



Figure 1 — Crest of Niagara escarpment 54 



" 2 — Rock face of Niagara escarpment 55 



" 3 — Face of lower ledge of Niagara escarpment 56 



Sayles : 



Figure 1 — Section of clay, Woodsville, New Hampshire 59 



" 2 — Section of clay, Woodsville, New Hampshire 60 



" 3 — Section of clay, Woodsville, New Hampshire 61 



" 4 — Section of till from the drumlin, called Winthrop Head. 



Boston Harbor 62 



