Geology. 333 



poorly known. Now from one locality 48 forms are at hand, and 

 of these 343 are here described for the first time. While there is a 

 time break of considerable duration between the Eocene and 

 Oligocene, "the climatic conditions of the Tejon and Lower OH- 

 gocene were much the same," and of a subtropical nature (165). 



In No. 7, the climatic zones of the Martinez or early Eocene 

 are described, showing that "the Martinez of the Los Angeles 

 basin was deposited in subtropical seas, while that of the San 

 Francisco basin was deposited in waters which more nearly cor- 

 respond to temperate conditions of to-day" (196). 



In No. 8, the author dissents from previous correlations in 

 regard to the Bowden, Alum Bluff, and the Orthaulax pugnax 

 beds, and concludes that they "are not upper Oligocene but 

 middle or lower Miocene" in age. The paper is essentially 

 devoted to indicating when the Atlantic was in open connection 

 with the Pacific through the Panama and Tehuantepec portals. 



"The Panama Portal was closed during Cretaceous time and 

 this gateway was not opened until upper Eocene time. During 

 a period of widespread uplift — Oligocene time — the Antilles 

 were probably connected with southern Florida and possibly 

 Central America. Following this emergent stage, a wide sub- 

 mergence occurred during Miocene time, marked by the 

 Bowden horizon. At this period North and South America 

 were disconnected and wide straits in Central America were 

 formed. Since the Miocene, the Panama portal has remained 

 closed." (205.) . 



"Spencer and Vaughan's conclusions concerning Pliocene 

 connections between the Atlantic and Pacific appear very 

 doubtful. This problem will be discussed at length in another 

 paper." (201.) 



"The evidence concerning the lower Oligocene or Vicksburg 

 stage is quite deficient and it is impossible to determine any 

 connections at this time. " (202.) c. s. 



Orbitoid Foraminifera of the Genus Orthophragmina from 

 Georgia and Florida; by C. W. Cooke and J. A. Cushman. 

 U. S. Geol. Survey, Prof. Paper 108-G, 1917, pp. 109-118, pis. 40- 

 44, text figs. 19, 20. — The first named author discusses the geologic 

 occurrence and faunal associates of the gigantic composite 

 foraminifer Orthophragmina, found in the Ocala limestone of 

 upper Eocene age ; while the second author describes seven new 

 species of this interesting genus. The half-tones are much 

 enlarged illustrations of these stellate foraminifers. c. s. 



2. Summary of Geological Besidts; by . Olaf Holtedahl. 

 Rept. Second Norwegian Arctic Expedition in the "Fram" 

 1898-1902, No. 36, 27 pp., 6 pis., 4 text figs., geological map. 

 1917. — In this interesting paper on the historical geology of 

 Ellesmere and Grinnell lands, the author brings together and 

 modernizes all that is known about the geologic sequence and 



