146 PROCEEDINGS OF THE AMHERST MEETING 



anticlinal structures which may not be recognized at the surface. In a similar 

 way the dip of the beds associated with salt domes may be indicated from a 

 study of well drillings. Each special field area has problems of its own, which 

 should be carefully studied before attempting to apply data from other areas. 

 The existence of underground faults may likewise be indicated by a study of 

 the foraminifera encountered in drilling across such structures. 



Presented by title in the absence of the author. 

 The session adjourned about 12.30 o'clock p. in. 



Session of Friday Afternoon 



The meeting - for the reading of pet.rologic, mineralogic, and economic 

 papers met Friday afternoon, under the chairmanship of President Kemp, 

 E. 0. Hovey acting as Secretary. 



TITLES AND ABSTRACTS OF TAPERS PRESENTED AT THE AFTERNOON 



MEETING AND DISCUSSIONS THEREON 



DECCAN TRAPS AND OTHER PLATEAU BASALTS 

 BY HENRY S. WASHINGTON 



(Abstract) 



The Deccan traps are a thick series of horizontal basaltic flows which issued 

 from fissure eruptions in the late Cretaceous and now cover about one-seventh 

 of the peninsula of India. They are of very simple and uniform mineral com- 

 position and ten analyses show that they are all much alike chemically. They 

 are quite typical basalts, except in their high content in iron oxides, mostly 

 ferrous, which is characteristic of them. Most of them contain considerable 

 glass. With the Deccan traps are compared the basalts of other extensive 

 "plateau eruptions,*' especially those of the Oregon region, the North Atlantic 

 ( including Iceland). Siberia, and Patagonia, many new analyses of the rocks 

 of which are given. All these plateau basalts resemble those of the Deccan 

 in their high iron content and simple mineral composition. The Archean 

 flows and sheets of the Lake Superior region and the Triassic traps of the 

 Eastern States appear to be very similar. 



It is suggested that the high iron content accounts for the great fluidity of 

 tbese basalts at the time of extrusion, which is characteristic of all the flows, 

 enabling them to spread in horizontal sheets over very extensive areas and 

 for long distances. The same chemical feature may also account for the quiet 

 character of their extrusion. The plateau basalts, in general, would appear 

 lo represent a special kind of basaltic rocks, and the bearing of this on the 

 idea of Atlantic and Pacific series, as well as on the question of the gravita- 

 tional distribution in the earth's crust, is briefly discussed. 



Presented extemporaneously. Illustrated by lantern slides. 



