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SCIENCE 



[N. S. Vol. XXV. No. 646 



range was studied by the fortieth parallel 

 and the Powell surveys in 1869-74 were 

 reviewed and the reasons given why those 

 studies were necessarily incomplete. After 

 referring to articles on separate parts of 

 the range by J. D. Irving (1896) and Chas. 

 P. Berkey (1905), the writer gave the con- 

 clusions he has been able to arrive at with 

 regard to its structure, and the age of the 

 older beds involved in the anticlinal fold; 

 together with some remarks on a new type 

 of topographic relief, as the result of field 

 studies made by him in company with Mr. 

 F. B. Weeks, during the summer of 1906. 



Stratigraphy and Structure of the Vinta 

 Mountains: F. B. Weeks. Read by title. 



Structure of the Franklin Mountains, 

 Texas: G. B. Richardson. (Introduced 

 by C. W. Hayes.) 



The Franklin Mountains are the southern 

 extremity of the long narrow range, known 

 locally by different names, that extends 

 southward from the Rocky Mountains, east 

 of the Rio Grande, as far as El Paso. They 

 are composed of sedimentary and igneous 

 rocks which range in age from pre-Cam- 

 brian to Cretaceous. The strata dip west- 

 ward from 20 to 75 degrees, and the moun- 

 tains as a whole have the appearance of a 

 block of the Basin Range type. The dis- 

 tribution of the strata shows that the range 

 is traversed by a complex system of faults. 

 Detailed sections of this uncommon struc- 

 ture were given. 



Prohdble Age of the Meguma (Gold-hear- 

 ing) Series of Nova Scotia: J. E. Wood- 

 man. Read by title. 



Artificial Production of Gneissic Struc- 

 tures hy Crystallization under Stress: 

 Fbed. Eugene Wright. 

 The generally accepted theory of the 

 formation of gneissic and schistose struc- 

 tures, as it has been developed, especially 

 by Van Hise, F. Becke and others, postu- 



lates stress as a fundamental factor con- 

 trolling the direction of crystal growth. 

 Experiments with silicate glasses of diop- 

 side, wollastonite and other prismatic or 

 tabular minerals, carried out in the geo- 

 physical laboratory of the Carnegie Insti- 

 tute, have shown that crystallization can 

 be made to proceed in the glasses at a tem- 

 perature much below the melting point of 

 the individual minerals, and while the glass 

 is still in a highly viscous state and capable 

 of sustaining a considerable amount of ap- 

 plied mechanical stress. Glasses of these 

 minerals were thus crystallized under 

 stresses acting either in one direction or in 

 two directions normal to each other, and a 

 parallel arrangement of the prismatic crys- 

 tals along definite planes or lines produced 

 similar to that which characterize gneisses 

 and schists. More recent experiments have 

 also been performed with a view of obtain- 

 ing a more definite idea of the order of 

 magnitude of pressure necessary to influ- 

 ence and control the direction of crystal 

 growth in such aggregates, and will be de- 

 scribed briefly. 



Origin of Meteor Crater {Coon Butte), 



Arizona: H. L. Faibchild. 



Four years of exploration and deep bor- 

 ing in and about the famous crateriform 

 basin in Arizona have revealed interesting 

 facts tending to establish the 'meteor 

 theory' of its origin. 



The Afton Craters: W. T. Lee. 



Two depressions, locally known as the 

 Afton craters, occur in southern New Mex- 

 ico, west of the Rio Grande, in the midst 

 of a broad sand plain which represents the 

 aggraded floor of the ancient Rio Grande. 

 The craters are comparable in size and 

 character with ' Coon Butte ' and the crater 

 of Zuiii Salt Lake. They differ notably 

 from ordinary volcanic craters, but are 

 situated in a region of recent volcanic aic- 



