510 



SCIENCE 



[N. S. Vol. XLI. No. 1057 



minished salinity. The eastern or Genesee beds 

 are restricted to New York and the states just 

 south. The base of the blaek shale of Ohio, Michi- 

 gan and Canada is younger than Genesee, as shown 

 by stratigraphic and paleontologio evidence. The 

 great fish fauna of these shales is shown by its oc- 

 currence and distribution to be primarily the fauna 

 of these sluggish rivers projected at intervals into 

 the brackish water of the embayments. The land 

 flora of Mississippia is also preserved in these 

 shales. The rivers of Appalachia and Atlantica 

 also had their fish fauna, but these were of different 

 types, their smaller size adapting them to these 

 torrential streams. With them occurred the sur- 

 vivors of the Eurypterids, which also inhabited the 

 rivers of the Paleozoic lands. The flora of Appa- 

 lachia and Atlantica is likewise largely distinct 

 from that of Mississippia. The deposits made by 

 these rivers were partly preserved as sandy deltas 

 and alluvial fans. 



"Symposium on the Passage from the Jurassic to 

 the Cretaceous." 



(1) The Morrison; An Initial Cretaceous Forma- 



tion: Willis T. Lee. 



(2) Origin and Distribution of the Morrison: 



Chables C. Mook. 



(3) Sauropoda and Stegosauria of the Morrison 



Compared with those of South America, Eng- 

 land and Eastern Africa: E. S. Lull. 



(4) The Faleobotania Evidence: E. W. Beert. 



(5) The Invertebrate Fauna of the Morrison: T. 



W. iStanton. 



Present Condition of the Volcanoes of Southern 



Italy: H. S. Washington and A. L. Day. 



A brief description of the general condition and 



state of activity at Vesuvius, Etna, Vulcano and 



Stromboli, as observed during the summer of 1914. 



Becent Eruptions of Lassen Peak, California: .T. 



S. DiLLEE. 



Lassen Peak, in northeastern California, at the 

 southern end of the Cascade Eange, has long been 

 considered an extinct volcano, but has recently 

 shown signs of rejuvenescence. The first of the 

 recent outbreaks occurred at 5 p.m.. May 30, 1914, 

 and since then many eruptions have occurred. The 

 nature of this remarkable phenomenon was illus- 

 trated and discussed. 



Physiographic Study of the Cretaceous-Eocene 



Period in the BocJcy Mountain Front and Great 



Plain Provinces: Geoege H. Ashley. 



The study of the rocks, especially of the coal 



beds, the structure and the life in the provinces 



named, appears to indicate that Upper Cretaceous 



time in that region was occupied by a single move- 

 ment of subsidence, somewhat irregular, but, on 

 the whole, persistent: that this was followed by a 

 period of general and differential uplift, to be fol- 

 lowed in turn by renewed subsidence, interrupted 

 locally, from time to time, by pronounced move- 

 ments of differential uplift. Comparison is made 

 between this interpretation and the assumed condi- 

 tions in the eastern United States and certain de- 

 ductions drawn as to the point in the time scale at 

 which the first general uplift occurred. 



Eelation of Physiographic Changes to Ore Altera- 

 tions: Wallace W. Atwood. 

 While a land mass is being dissected, the ground- 

 water table is slowly lowered through that mass, 

 until, at the peneplain and base-level stages, the 

 groundwater table remains almost stationary for 

 long periods of time. During successive cycles of 

 erosion the position of the base-level of erosion in 

 the land mass being dissected must change, and, 

 if climatic conditions remain constant, such 

 changes are necessarily accompanied by changes 

 in the position of the groundwater table. ^ If 

 the land mass is elevated, the base-level will be 

 lowered through the land, and the groundwater 

 table will be slowly lowered. When a land mass is 

 depressed, the base-level of erosion and the ground- 

 water table are elevated throughout that land mass. 

 Moist climates will raise the groundwater table, 

 and dry periods lower that table. As the ground- 

 water table is raised or lowered, the zones in which 

 the chemical changes associated with the secondary 

 alteration of ore deposits take place are varied in 

 thickness. 



These facts indicate that physiographic studies 

 may be profitably applied in the study of ore alter- 

 ations, and conversely that the record of ore alter- 

 ations may furnish important data bearing upon 

 the physiographic evolution of the districts con- 

 cerned. 



The study of secondary ores by various investi- 

 gators has called for intensive physiographic 

 studies. During the past season field work waa 

 done in the vicinity of Butte, Montana, and Bing- 

 ham Canyon, Utah, to determine the relationship of 

 physiographic evolution to the secondary enrich- 

 ment of ores in those regions. In this paper the 

 problem of the application of physiography to the 

 investigation of secondary ores was defined, and 

 some of the results of the past season's field work 

 were presented. 



Graphic Projection of Pleistocene Climatic Oscilla- 

 tions: Chester A. Eeeds. 



