ABSTRACTS OF PAPERS 157 



tary was authorized to convey the Society's appreciation to the members 

 of the local committee. 



At 1 o'clock the Society adjourned for luncheon, to meet again at 2 

 p. m. in two sections. 



The first paper in the afternoon session of the section of invertebrate, 

 paleobotanic, and general paleontology was presented by the author and 

 illustrated by drawings; 15 minutes. 



EVOLUTION OF THE ANTHOZOA AND THE SYSTEMATIC POSITION OF 



PALEOZOIC CORALS 



BY T. C. BKOWN 



(Abstract) 



lu the developuieut of the zooids of modern Anthozoa a stage is always 

 observed in whicLi there are eight mesenteries present. This condition may 

 persist throughout life, as, for example, in the subclass Alcyouaria ; or it may 

 be only transitory, as it is in the subclass Zoantharia. 



To the subclass Alcyouaria probably belong those Paleozoic corals that are 

 either without septa or iu which the septa probably were not directly related 

 to the internal mesenteric structure of the zooid — Columnaria, Favosites. 

 Syringopora, etcetera. 



In the subclass Zoantharia four distinct orders can be recognized, and these 

 orders are distinguished by the number and arrangement of the mesenteries 

 added beyond the primitive number eight. In the Cerianthidea new meseu- 

 teries are added at only one point in the periphery of the zooid ; in the 

 Zoanthidea they are added at two points ; in the Tetracorallidea at four points : 

 in the Actiniidea at many points; generally some multiple of six. The first 

 two of these orders are known only from modern forms; the third is confined 

 to the Paleozoic ; the fourth probably begins in the Mesozoic and is dominant 

 at the present time. 



The second paper of the afternoon was given by the author and illus- 

 trated by lantern slides and diagrams; 15 minutes. Discussed by Charles 

 Schuchert, P. E. Raymond, J. M. Clarke, and A. W. Grabau. 



NEW FACTS BEARING ON THE PALEOZOIC STRATIGRAPHY OF THE REGION 



ABOUT TJlin:E FORKS, MONTANA 



BY W, P. HAYNES 



(Abstract) 



Iu the various sections studied in the region about Three Forks and the 

 adjacent country to the south, in southwestern ^^ontana, the Jefferson lime 

 stone lies in apparent conformity on the Cambrian limestone, without any 

 intervening formations. From I'aleozoic evidence all of the Jefferson lime- 

 stone is regarded as of Devonian age, and it is considered to lie disconform- 

 ably on the Cambrian limestone iu this region. 



