Doll — Miocene and Pliocene of Martha's Vineyard. 301 



species were common to the Santee (Eocene) and Ashley beds. 

 One of these species is inedited, another is an unrecognizable 

 internal cast {Gonus gyratus) the last is Nautilus alahamensis. 

 Two other Eocene forms are mentioned b}^ Tuomey as belong- 

 ing to the Ashley River marl, Pecten calvatus and Panopcea 

 elongata. The Cretaceous Gryphcea mutabilis and the very 

 uncertain Anomia jugosa complete the list of known species 

 among those which were named, but not described or figured, 

 by Tuomey. It is by no means unlikely that such of these as 

 are really Eocene may have been derived, like the Gryphcea, 

 from subjacent deposits. Tuomey says in regard to the Ashley 

 marl (op. cit. p. 165), " Mr. Ruffln was struck with the absence 

 of all the more common Eocene forms of Virginia and even of 

 the Santee " and (p. 167) " Venus crassa (T. mss.) bears so 

 strong a resemblance to the Miocene species V. lyrata Conr. 

 that it was not without hesitation that I separated them. Gar- 

 dita dubia (T. mss.) can scarcely be distinguished from a spe- 

 cies found in the Miocene of Pamunkey, Ya. Y. proxinia 

 (T. mss.) is like V. cortinaria / in a word, any one acquainted 

 with our fossils would be struck with the Miocene aspect of 

 these ; and had I not found them associated with Gryphcea 

 mutabilis, Pecten calvatus, Gonus gyratus and Panopwa elon- 

 gata, I would not have ventured to place them here." 



The pecten referred to is not P. calvatus, and it is obvious 

 that the Eocene age of the Ashley marl is in great need of 

 confirmation. An examination of the casts of fossils in the 

 phosphatic nodules shows about twenty species, of which the 

 most common are an undescribed species of Venus, Astarte 

 vicina Say, an Amusium not distinguishable from A. mortoni 

 jr., Lucina contracta Say, Dentalium attenuatum Say, and a 

 Venericardia different from but related to V. granxdata Say. 

 Beside these are species of Gorlmla, Leda, IToldia, Pecten 

 {decemnarius Say), Tellina, Glivella, Marginella, Solen, Modi- 

 ola, and Balanophyllia. Lastly, among the gutta percha 

 squeezes taken from the casts were two unmistakable frag- 

 ments of Ecphora, quadricostata. All the identified species 

 are well known Miocene shells and all the others may well be 

 Miocene. iNot a single Eocene species, or characteristic 

 Eocene type, occurred in the whole collection. 



I have no hesitation in concluding therefore that the rock 

 from which the phosphatic nodules are derived is of upper 

 Miocene age, or at least that its fauna, while unmistakably 

 Miocene, is more nearly related to the Chesapeake Miocene 

 than to the older beds of the Chipola epoch. The phosphati- 

 zation of the rock was of course later than its formation and 

 perhaps might have taken place, like that of the very similar 

 Peace River, Florida, phosphatic pebbles, during Pliocene 

 time. 



Washington, July 20, 1894. 



