Geology and Natural History. 423 



to show the stages through which the particular form has passed 

 in its development from earlier times. The genus Liriodendron, 

 as is well known, is a waning type only a single species, or pos- 

 sibly two, remaining in the present flora of the globe, while a 

 large number of fossil species have been described, many of 

 which have leaves which remind us strongly of these embryonic 

 early forms figured by Mr. Holm. As these embryonic forms, 

 however, are not likely to occur in a fossil state, Mr. Holm's 

 contention that there has been an undue multiplication of species 

 by paleobotanists, and that many of the fossil species described 

 are only early forms of living species, is by no means sustained, 

 and be does not seem to understand that these modern embryonic 

 forms are more likely to represent the phylogenetic stages through 

 which the present living species has passed. l. f. w. 



4. Contributions to the Tertiary Fauna of Florida ; by Wm. 

 H. Dall. Trans. Wagner Free Institute of Sci., Philadelphia, 

 vol. iii, pt. i, Aug., 1890. 178 pp., 12 plates. — The excellent plan 

 of this series of publications, that of presenting memoirs on the 

 geology and paleontology of Florida, is well exemplified in the 

 present issue. It is aimed to produce a complete monograph of 

 the molluscan fauna of the Caloosahatchie beds, which shall serve 

 as a typical example of an American Tertiary fauna, and as a 

 standard for critical comparisons with other horizons. The 

 present number comprises the greater part of the gastropods, and 

 is to be followed by the second part, to include the remainder of 

 the gastropods, together with the pelecypods and scaphopods. 

 The material employed was collected by Mr. Joseph Willcox, the 

 the author, Mr. Frank Burns of the U. S. G. S., and others. 



An important discussion in dynamical evolution, relating to 

 the plications on the columella in the Volutidse, leads the author 

 to conclude that they are the strongest in those shells hav- 

 ing the most deep seated adductor muscles. Also, that the 

 plications are produced by the frequent retraction of the animal, 

 and consequent wrinkling of the large shell-secreting mantle 

 when withdrawn within the shell cone while enclosing the com- 

 paratively firm foot and body of the animal. Through an 

 extension of this principle the author also accounts, by similar 

 mechanical reasous, for the teeth and lirae so common and char- 

 acteristic in many other groups. c. e. b. 



5. On Syringothyris Winchell, and its American Species; 

 by Chakles Schuchert, from the Ninth Ann. Rept. N. Y. State 

 Geologist. 12 pp. 1890. — The question as to what should consti- 

 tute the type species of Spirifer and Syringothyris is discussed 

 by the author, and considerable light thrown on the synonymy of 

 the American species belonging to the latter genus. Syr. Carteri 

 Hall is shown to be the same as Syr. typa Winchell, and therefore 

 becomes the type. Following Davidson and others Spirifer stri- 

 atus is accepted as the type of Sowerby's genus, although Syr. 

 cuspidatus was the first species referred "to Spirifer. c. e. b. 



6. Mineral Resources of the United States. — Calendar year 

 1888, David T. Dat, Chief of Division of Mining Statistics and 



Am. Jour. Sci.— Third Series, Yol. XL, No. 239. — Nov., 1890. 

 26a 



