abstracts: geology 505 



sent the feather edge of a series of coal-bearing rocks in the lower part 

 of the Colorado group recognized in northern Arizona, southwestern, 

 west-central, and northern Utah, and southwestern Wyoming. 



A large part of the report consists of a description of the coal, which 

 is bituminous and occurs principally in the above mentioned sand- 

 stone. A little coal is present in the Dakota sandstone but is not 

 economically important. A large amount of coal is contained in the 

 Mesaverde formation in Wasatch Plateau, but it was not extensively 

 studied. C. T. L. 



GEOLOGY. — The 'physical conditions and age indicated by the flora of 

 the Alum Bluff formation. E. W. Berry. U. S. Geological Survey 

 Professional Paper 98-E. Pp. 18, with illustrations. 1916. 

 This paper describes a small flora from the Alum Bluff formation in 

 Liberty County, Florida. This flora represents a horizon hitherto un- 

 represented paleobotanically in southeastern North America. It is con- 

 cluded that the Alum Bluff formation as a whole is a predominantly 

 shallow water deposit of clays and sands, and that the flora preserved 

 at Alum Bluff records the last phase of sedimentation before the area 

 emerged from the sea. The most profound break in Tertiary sedi- 

 mentation in the southeastern United States is represented by the 

 unconformity at the top of the Alum Bluff formation. R. W. S. 



GEOLOGY. — The Chisana-White River district, Alaska. Stephen R. 

 Capps. U. S. Geological Survey Bull. 630. Pp. 126, with maps, 

 sections, and views. 1916. 

 The Chisana-White River district comprises that portion of the 

 White River basin which lies west of the international boundary and 

 the headward portion of the Chisana River basin east of that river and 

 south of the north front of the Nutzotin Mountains. The oldest rocks 

 of the district are basic lavas and pyroclastics with a considerable 

 amount of black shale of Devonian age. The next succeeding system, 

 the Carboniferous, comprises a great thickness of interbedded lavas, 

 tuffs, agglomerates, and breccias, containing very little sedimentary 

 material. Upon these lies a bed of massive limestone, associated with 

 thin-bedded limestones and shales. Above the limestones and shales 

 is a great thickness of lavas and pyroclastic rocks similar to those 

 mentioned, again interrupted by other massive limestones. These in 

 turn are succeeded by other bedded basic lava flows, which form the 

 highest part of the Carboniferous system recognized in this district. 



