310 . REVIEWS 



In this paper it is shown that between the basal Eocene deposits, 

 or Midway Stage, and the uppermost Cretaceous, there is in the south- 

 ern states a decided break, both stratigraphic and faunal, so that not a 

 single species is known certainly to have crossed from one formation 

 to the other. These initial beds of the Eocene are treated both geo- 

 logically and faunally by Professor Harris. The field investigations 

 were carred on in the states of Texas, Arkansas, Tennessee, Mississippi, 

 Alabama, and Georgia. From his studies Professor Harris is led to 

 believe that a considerable time interval elapsed between the close of 

 the Cretaceous deposition and the beginning of the Eocene deposition 

 in the Mississippi basin, and that wherever good contact exposures are 

 found, there may be found, on careful study, ample evidence of non- 

 conformity. 



This initial Eocene fauna is discussed at length, all the old species 

 of Mollusca and many new ones are described and figured. 



5. "A reprint of the palseontological writings of Thomas Say; 

 with an introduction, by G. D. Harris. Pp. 271-354. Plates XXVI- 

 XXXII. (December 7, 1896.) 



The republication of these papers, originally published from 1819 to 

 1825, long since out of print and accessible only in the larger libraries, 

 will be appreciated by all those who have had occasion to refer to such 

 literature, and have been unable to find access to it. The following 

 papers are republished, word for word, line for line, and page for page, 

 as written and punctuated by the original author : 



I and 2. " Observations on some species of zoophites, shells, etc., 

 principally fossil. Am. Jour. Sci., ist ser., Vols. I and II (1819-1820). 



3. "Fossil shells found in a shell mass from Anastasia Island." 

 Jour. Acad. Nat. Sci., PJiil., ist ser.. Vol. IV (1824). 



4. "An account of some fossil shells of Maryland." Jour. Acad. 

 Nat. Sci. Phil., ist ser.. Vol. IV (1824). 



5. "On two new genera and several species of Crinoidea." Jour. 

 Acad. N'at. Sci. Phil., ist ser., Vol. IV (1825). Stuart Weller. 



Eocene Deposits oj the Middle Atlantic Slope in Maryland, Delaware 

 arid Virginia. By Wm. Bullock Clark, U. S. Geol. Sur., 

 Bull. 141, 167 pp., 40 pis., 1896. 

 During the first half of the century the Tertiary formations of 



eastern United States were among the most carefully studied and best 



