766 



ABSTRACTS OF PAPERS 



river, Bonneheur, flows uuder an arch about 40 feet wide and 30 high, emerges 

 again to daylight at the distance of about 500 feet, then plunges under another 

 arch, flows some 4,000 feet, to emerge finally, with a depth of 16 feet, in a 

 cataract 35 feet high under a stupendous arch, estimated to be 300 feet high. 

 Although styled a cave, the Bramabiau is really a gigantic natural bridge. 



SALT MARSH FORMATION NEAR BOSTON, AND ITS QEOLOQICAL 

 SIGNIFICANCE 



BY CHABLES A. DAVIS^ 



(Abstract) 



A description of some of the salt marshes near Boston, including newly dis- 

 covered facts regarding the way in which they are formed and their bearing 

 on geological history. These marshes have not been formed in depressions 

 behind barrier beaches as the result of filling by plants and sediments in the 

 resulting ponds, but have a quite different origin, which is plainly indicated 

 in their structure and in the character of the plant material contained in 

 them. The marshes contain easily interpreted records of a continued post- 

 Glacial coastal subsidence that is still going on at a steady and uniform rate 

 that it is possible to determine. The interpretation of these deposits also has 

 an important bearing on the theories of formation of coal. 



GEOLOGICAL SUGGESTIONS DERIVED FROM A NEW ARRANGEMENT OF THE 



ELEMENTS 



BY B. K. EMERSON 



I 



(AJ)Stract) 



The elements were arranged in the order of the periodic law on an increas- 

 ing helix — that is, on a half octave, two octaves, and four double octaves — and 

 interesting physical and geological relations were brought out. 



MECHANICS OF FAULTS 

 BY HABEY FIELDING REID 



(Abstract) 



The forces which can be considered as active in producing faults are : hori- 

 zontal tensions and compressions, vertical forces (upwards or downwards), 

 and horizontal drags on the under surface of the crust. It was shown that in 

 a uniform crust horizontal forces alone would produce normal or thrust faults 

 having hades of 45 degrees ; that the available vertical forces alone would pro- 

 duce normal faults with a smaller hade, and that the addition of a tension to 

 a vertical force increases the hade, whereas the addition of a pressure dimin- 

 ishes it. Drags generate pressure and tensions ; they may cause faults with 

 horizontal displacements. The elevation of large regions is due to vertical 

 and not to tangential forces. 



8 Introduced by David White. 



