﻿324 Scientific Intelligence. 



sheet was recognized as of contemporaneous overflow origin, and 

 consists of monotonous diabase, with alteration throughout : on 

 the other hand, certain necks or plugs of lava, seen breaking across 

 the sandstones, and of roughly circular area, are found to be un- 

 changed by alteration, and to possess a veiy glassy base. Evi- 

 dence was found in the steep faces of some fault bluffs for the 

 recent occurrence of dislocation in this region. 



Bernardston Devonian, in the Connecticut valley. — Professor 

 Emerson also showed a map of the Bernardston Devonian lime- 

 stone district in northern Massachusetts, in which the distribution 

 and attitude of the rocks were displayed with much detail. 



Origin of the JPottsville and other Conglomerates. — The origin 

 of wide-spread and heavy conglomerates, such as the Pottsville, 

 was discussed by Mr. Brankee, who preferred to explain them 

 by the action of tidal bores, such as occur on the Amazon. He 

 pointed out that in favorable conditions, the bore may have an 

 extended development and not be limited only to the mouth of a 

 river. Dr. Comstock supported him in this view. Mr. Davis point- 

 ed out the need of a strong transporting agent in the origin of con- 

 glomerates that consist of materials unlike the rocks on which they 

 lie, but on account of the local nature of the tidal bore looked 

 rather to general stronger tides. for the needed agent, and Mr. 

 Claypole took similar ground. Mr. Merrill showed that not only 

 the transportation but the origin of certain gravels in New Jersey 

 awaited explanation. 



Distortion of Cretaceous and Tertiary beds on Long Island and 

 the islands east of it. — In illustration of some dynamic effects of 

 the ice sheet, Mr. F. J. H. Merrill of New York described the 

 distortion of certain Cretaceous and Tertiary beds on Long Isl- 

 and and southern New England, including those of Gay and San- 

 katy Heads. Many morainic ridges were found to owe their height 

 in good part to anticlinal deformation of the beds below them 

 by glacial thrust ; stratified deposits containing post-Pliocene 

 shells were thought to be older than the Champ] ain epoch, and 

 their present altitude was regarded as the result rather of local 

 glacial disturbance than of continental elevation. 



Recent geological anticlinals. — "An account of some new 

 geologic wrinkles " served Mr. Gilbert as an introduction for 

 an ingenious hypothesis. He has lately discovered several small 

 post-glacial anticlinals in the horizontal limestones of Jefferson 

 Co., N. Y. and in the shales near Dunkirk, in the western part of 

 the State, and suggests that they may have resulted from expan- 

 sion caused by the warming up of the surface layers of the rocks 

 as they recovered from the cold of the Glacial period. 



The titles of all the papers accepted for reading in the Geolog- 

 ical Section are given on pages 330 and 331. 



2. Bvachiopoda and Lamellibranchiata of the Raritan Clays 

 and Greensand Marls of JVeio Jersey ; by Robert P. Whit- 

 field. Vol. I. 270 pp. 4to, with 35 lithographic plates of fossils 

 and a colored geological map of part of the State. Geological Sur- 



