VI BULLETIX OF THE GEOLOGICAL SOCIETY OF AMERICA 



Page 

 Plate 8 — SpENCEK : Main mountain trends of British Columbia, Yukon, and 



Alaska 118 



9 " Level sky-line of the Chugach plateau 121 



10 " Mountains separatino; drainage of Copper and Yukon 

 rivers 123 



11 " A portion of the Chugach mountains 125 



12 " Relation of Copper and Alsek rivers to coastal mountains. 127 



13 " Copper river 128 



14 — Fuller and Clapp: Stratification in marl-loess and in sand dunes. . 160 



15 " '•' " Profile and surface of marl-loess terraces 163 



16 — Williams : Comparative chart of Devonian sections 177 



17 — AViLLis : Slopes of Ames knob, North Haven, Maine. 203 



18 '■ Slope of Ames knob and pit in glacial gravel 205 



19 — Spencer : Submarine valleys of the Atlantic coast ... 208 



20 " Submarine valleys of the jSorth Atlantic and Arctic basins. 218 



21 — xSewsom: Dikes on Graves creek, near Asuncion, California 232 



22 " Dikes on Graves creek, near Asuncion, California 233 



23 " Dikes on Graves creek 234 



24 " Bituminous sandstone dike and west end of dike 30 240 



25 " East end of dike 30 243 



26 " Dikes 38 and 41 244 



27 " Dike 41 245 



28 '' Sandstone dikes 246 



29 " Details of the Respini Creek intrusion 247 



30 " Details of Respini Creek dike and dike 52 248 



31 " Sandstone dikes in coal beds 253 



32 — HicE : Bed of Beaver river 299 



33 " Potholes below Fallston dam : 300 



34 " Potholes below Fallston dam 301 



35 " Potholes below Fallston dam 302 



36 " Potholes near Rock ponit 303 



37 — Kemp and Knight: Geological map of the Leucite hills, Sweetwater 



county, AVyoming 309 



38 " " " Photomicrographs of wyomingite and orendite. 314 



39 " " " Emmons mesa, Red cone, and Hatcher mesa. . 316 



40 " " " Group and members of tlie Leucite hills 318 



41 " " " Cleft near escarpment and North and South table 319 



42 " " " Photomicrographs of wyomingite 321 



43 " " " Orenda, Black Rock, and Steamboat mesas. .. . 323 



44 " " " Badgers teeth 326 



45 " " " Boars tusk 328 



46 " " " Madupite from Pilot mesa 331 



47— Grabal : Coral reef in Alpena limestone . . 338 



48 " View of reef shown in plate 47 339 



49 — Todd : Concretions, their structure and effects 366 



50 ' ' Various concretions 368 



51 " Log-like concretions 368 



52 " Concretion horizon and natural revetment 368 



53 " Concretions in Wyoming 368 



