REVIEWS 3 2 7" 



upper teeth, Dr. Wortman has been enabled to interpret the somewhat 

 fragmentary remains of the other genera and to make out what he 

 believes to be, not only their affinities to each other, but what is still 

 more important, to demonstrate their genetic relationship to the later 

 appearing American Edentata. 



The genera included in the suborder are Conoryctes, Onychodectes, 

 Hemigamis, Pisittacotherium, Calamodon, and Styhnodon. In the treat- 

 ment of the relationship of these genera to the Edentata, seventeen 

 points of resemblance are enumerated, and they are considered as a 

 primative suborder of and the ancestors of the Edentates. 



The South American Edentates appear suddenly in the Santa Cruz 

 formation in great numbers and variety with apparently no previous 

 announcement in the older deposits. This fact would seem to indicate 

 that they were immigrants from another region. While the Santa 

 Cruz beds cannot yet be accurately placed in t-he time scale, it is highly 

 probable that they are not older than the North American Oligocene. 

 In North America the Ganodonia appear in the very earliest Puerco- 

 deposits and continue without interruption into the Bridger, where 

 they disappear. 



If Dr. Wortman's conclusions as to the relationship of the Gano- 

 donta to the Edentata be correct, as they seem to be, the geographic 

 distribution of the groups would suggest that during Eocene time there 

 was at least a temporary connection between the North and South 

 American continents, allowing the immigration from the north, of the 

 ancestors of the South American Edentate fauna. 



Article XI. Description of New Species of Silurian Fossils from near 

 Fort Cassin and elsewhere on Lake Champlain. By R. P. Whitfield, 

 pp. 177-184. Plates IV-V. 



The fauna of the Fort Cassin beds on Lake Champlain is one of 

 remarkable interest. Its position is in the Lower Ordovician, in the- 

 upper part of the Calciferous formation. As a rule the Calciferous 

 strata do not furnish an abundance of fossils, either specifically or 

 individually, but the Fort Cassin beds are an exception. Two previous 

 papers containing descriptions of species from this bed by Professor 

 Whitfield 1 have appeared, so that in all 60 species are now known, 

 distributed as follows, 25 gastropoda, 17 cephalopoda, 8 trilobites, 7 

 brachiopoda, 2 Crustacea (not trilobites) and 1 bryozoan. 



1 Bull. Am. Mus. Nat. Hist., I, p. 293, and Bull. Am. Mus. Nat. Hist., Ill, p. 25. 



