INSTITUTE OF SCIENCE, PHILADELPHIA. 64* 



that a recent rock of this kind has been noted as occurring on the west 

 coast. 



A similar rock, now rapidly undergoing destruction through the wash 

 of the sea, guards the entrance to Little Sarasota Inlet. On White Beach, 

 on the inner side of the inlet, probably two and a-half or three miles from 

 its mouth, a reef-rock, very tough in places, and extensively honeycombed 

 through the action of the water, forms the shore line, and doubtless, also 

 constitutes in greater part the bottom of the bay. Unfortunately, the 

 fossils, which are markedly abundant, are in the main in a very bad state of 

 preservation, and for the most part do not admit of specific determina- 

 tion. The impressions of reef-corals, probably a species of madrepore, 

 are numerous, and we also found several casts of apparently the same 

 species of simple coral which has been noted as occurring in the sandrock 

 at Whittaker's. Most of the molluscan remains are in the form of casts 

 and impressions, and belong chiefly, at least as far as the more prominent 

 forms are concernftl, to Pecten, Cardium, Area, Venus and Turritella, the 

 last being by far the most abundant of the gasteropod genera, and in our 

 own collections almost the only one represented. The rock is either 

 of Miocene or Pliocene age, but I could not positively determine which, 

 although from its position, and in the light of our present knowledge 

 regarding the formations on the Caloosahatchic, I should consider it not 

 far from the junction line of the two scries, if it does not, indeed, effect 

 a passage between the two. The only forms that appeared to be recog- 

 nizable, and even these were somewhat doubtful, were fragments bearing 

 a close resemblance to Pcctcn Jcffcrsonins, I'cnns alveata and one of the 

 northern forms of Turritella. 



In a rock manifestly belonging to the same series, although of a 

 somewhat different lithological aspect, we found numerous casts of one 

 or more species of large oyster, one of them, with little doubt, the 

 Ostrca Virginiana, in association with which were the casts also of a 

 cockle (Cardium magnum?), clam (Venus Mortoni ?), and a Perna. 

 Many of these were lying loose on the beach, having been evidently 

 washed out from the parent rock. A short distance beyond this point, 

 where a not exactly insignificant creek has cut a nearly vertical channel, 

 the rock is exposed in heavy beds of from one to two feet thickness, 

 rising to a total height above the creek of some eight or ten feet, or 

 possibly more. Among the fossils gathered here, which were neither 

 numerous nor well-defined, there were a number of gasteropod casts, 

 probably Turritellas, and fragments of a large scallop which bore a strong 

 resemblance to Pcctcn Madisonius. 



ROCKS OF THE CALOOSAHATCHIE. The remarkable series of deposits 

 exposed on this river, which I have designated the " Floridian," and 



