334 STUART WELTER 



A careful analysis of this fauna of the Cliffwood clays brings 

 clearly to view several important facts. In the first place, the large 

 number of species which are common to the fauna, and to one or 

 more of the faunas of the formations above, emphasizes the close 

 relationship between the Cliffwood fauna and these higher faunas. 

 This relationship is, indeed, so close that they constitute essentially 

 but different faunules of one large fauna. There is no sharper dis- 

 tinction between the fauna of the Cliffwood clays and the Merchant - 

 ville clay than there is between the Merchantville and the Woodbury 

 clays. However, the Cliffwood fauna does possess characteristics 

 which distinguish it somewhat sharply from the Merchantville fauna, 

 among which may be mentioned the abundance of the species Pteria 

 petrosa and Isocardia clifjwoodensis, which have nowhere yet been 

 recognized in the Merchantville, and the especial abundance, in some 

 cases at least, of Veleda lintea, which is sometimes present, although 

 always rare in the Merchantville. None of the crustaceans which 

 are so abundant in the Cliffwood fauna have been recognized in the 

 Merchantville, although claws and other disarticulated joints of 

 crustacean appendages are not uncommon in the higher fauna at 

 some localities. The distinction between these two faunas is not alone 

 emphasized by the species present in the Cliffwood and absent from 

 the Merchantville, but also by the genera and species which are absent 

 from the Cliffwood and almost universally present in the Merchant- 

 ville fauna. Among such genera may be mentioned Idonearca, 

 Trigonia, Panopea, Axinea, and Leiopistha. 



On making a careful comparison between the Cliffwood fauna 

 and that of the Woodbury clay, the formation immediately above the 

 Merchantville, a much greater resemblance is noted than between 

 the Cliffwood and the Merchantville; the same Merchantville genera 

 mentioned above as being conspicuously absent from the Cliffwood 

 fauna are also conspicuous for their absence from the Woodbury. 

 Furthermore, several forms are common to the Cliffwood and the 

 Woodbury faunas which have not been observed in the intervening 

 formation, among which may be mentioned Breviarca, Lucina cre- 

 tacea, and the little crustacean here called Tetracarcinus subquad- 

 ratus. In making this comparison, however, it must not be overlooked 

 that some of the most characteristic Cliffwood species, as Isocardia 



