STRUCTURE OF THE HELDERBP^RG FRONT 747 



east of the Hudson is partly indicated by Becraft Mountain and Mount Ida. 

 The basal part is of folded Hudson strata uneonforniably succeeded by late 

 Siluric, showing various phases of overlap. The Appalachian folds are of the 

 usual asymmetric type, while the range from near Rosendale to Catskill and 

 beyond is complicated by one or more pronounced overthrusts. The first of 

 these was described by the author from Kingston, and subsequently more fully 

 discussed by Van Ingen and Clark. Chadwick has described a part of the 

 thrust at Saugerties and the author has determined its character near Catskill. 

 Several new sections from this last region were presented. 



Discussion 



Prof. J. B. WooDwoRTH called attention to the fact that in southeastern 

 New England the carboniferous areas show overthrusts to the southeastvvaitl 

 and not to the westward. Jt should not, therefore, be assumed, as has been 

 done, that there has been everywhere in the Appalachian geological province 

 an overthrust as from the Atlantic basin. 



SUCCESSION IN AGE OF THE VOLCANOES OF HAWAII 

 BY T. A. JAGGAR, JB. 



(Abstract) 



The plan of the Island Hawaii shows a symmetry in accordance with the 

 structure of the several volcanoes, and the activity of two of them, which 

 leads to the conclusion that there is a record of succession shown. This is at 

 variance with Button's conclusion that no age of beginning of activity for a 

 given vent can be assigned. The writer not only postulates a succession in 

 age of beginning and closing activity in the older vents, but he argues that 

 Kilauea is not the youngest vent. The argument presented suggests a perma- 

 nent lava column continuously rising. 



BIBLIOGRAPHY OF THE MAMMOTH GAVE 

 BY HOEACE C. HOVEY 



(Adstract) 



This catalogue contains the titles (with brief descriptive notes) of all known 

 publications concerning Mammoth Cave and its contents, comprising descrip- 

 tions of its antiquities, scenic features, geology, environment, cavern fauna, 

 and flora. 



LII— Bull. Geol. SoC. A.m., Vol. 23, 1911 



