TITLES AND ABSTRACTS OF PAPERS 81 



rise of the gases to the surface. In support of this, it was also observed that 

 when the quantity of gas set free was large the temperature of the liquid 

 lava in the basin was higher (July 6, 1912, 1,185°) ; when the amount of dis- 

 charged gas was small it was lower (June 13, 1912, 1,070°), the quantity of 

 lava in the basin remaining substantially the same. 



Controverting a view recently put forth, H2O was found to be present as 

 such among the gases set free, as indeed it inevitably must be, for it has long 

 been known that free hydrogen in association with SO2 and CO2 will react to 

 form water at these temperatures. 



Neither hydrocarbons nor chlorine in appreciable quantities was found. 



The absence of argon is definite evidence that none of the gases composing 

 the volcanic emanation are of meteoric origin. 



The paper is somewhat preliminary in character, and will be followed by 

 more detailed studies of the relation of the gases to each other and to the 

 lava at the temperatures which prevailed in the volcanic vent. 



After Doctor Day's lecture, the Society repaired to Guyot Hall, where 

 the general session was called to order, with President Eugene A. Smith 

 in the chair. 



By vote, the Council report was taken from the table, accepted and 

 ordered printed in full in the Proceedings. 



After several announcements had been made by the Secretary, the 

 Society proceeded at 11 o'clock to the consideration of the scientific 

 papers. 



TITLES AND ABSTRACTS OF PAPERS PRESENTED IN GENERAL SESSION AND 



DISCUSSIONS THEREON 



STRATIGRAPHY OF RED BEDS OF NEW MEXICO 



BY N. H. DARTON 



i Abstract) 



The author presented an outline of results of detailed study of part of Red 

 Beds area of New Mexico during the past summer. The investigation was 

 mainly to determine areas in which chemical deposition had continued longest. 

 Outcrop zones were followed continuously and stratigraphic changes traced in 

 detail. The results show the equivalence of formations differentiated in vari- 

 ous areas and throw much light on conditions of sedimentation during Penn- 

 sylvania-Triassic time. 



Discussion 



Dr. Whitman Cross : The sedimentary section described by Mr. Darton is 

 very different in some particulars from that which has been studied in much 

 detail in the adjacent portion of Colorado. In the analysis of the New Mexico 

 sections it will be helpful to identify two horizons which have been found in 

 Colorado to represent important stratigraphic breaks. One of these is at the 

 base of the vertebrate-bearing Upper Triassic sediments; the other is at the 

 base of the La Plata Jurassic sandstone. 



VI — Bull. Geol. Soc. Am., Vol. 25, 1913 



