Formations of the Hampshire Basin. 443 



runs out of the cliff near Barton Gang, where it thins out in a 

 singular manner. It is seen " in situ," forming the walls of the 

 ravine called Beacon Bunny, where it is capped with the gray 

 sand No. 17. It measures about 25 feet. The fossils are dis- 

 tributed throughout the entire bed. The nacreous laminae of the 

 bivalves, and the enamel of the Oliva ave finely preserved. It 

 differs lithologically from all the other beds in the section, and 

 forms the uppermost true marine stratum of the Barton group. 

 We collected from this clay the following shells : — 



Avicula, n. sp. Tellina Isevis, Edw. 

 Cardium turgidum. Sow. Very large Ancillaria subxilata. Lam. 



specimens. Buceinum lavatum. Sow. 



Cytherea ti-ansversa. Sow. desertum. 



Corbula. _ Natica striata. Sow. 



Mactra. patula. Lam. 



Nucula trigona, Sow, Oliva Branderi, Sow. 

 VenericarcUa globosa. Sow. 



Bones of fishes and fragments of the skeleton of a large Turtle 

 have been found in this bed, along with pine-cones, and other 

 vegetable debris. 



No. 19. Gray sand rises to the west of Beacon Bunny, and 

 runs out of the cliff beyond Barton Station. No fossils have 

 hitherto been found therein. It measures about 20 feet. 



No. 20. The Barton gray sand, or " Chama bed," rises on the 

 shore, about half a mile to the eastward of Beacon Bunny, and 

 runs out of the cliff half a mile west of Barton Station. It is 

 much concealed by the shingle of the beach, which requires to 

 be removed before the bed can be worked. From this rich stra- 

 tum many fine shells are collected. It contains an immense pro- 

 fusion of Chama squamosa, from which circumstance I have named 

 it the " Chama bed." Much difficulty was experienced in mea- 

 suring this bed, which varies from 10 to 15 feet in thickness. 

 Where the sand rises on the beach it is concealed by shingle, and 

 in its course through the cliff it is covered up by the debris of 

 other beds. The most beautiful specimens of the Barton shells 

 are obtained from this I'ich fossiliferous stratum. We collected 

 the following species from the gray sand, and have little doubt 

 that future investigations will add many more to the list. The 

 majority of the species are special to it. 



CONCHIFEKA. 



Area Branderi, Sow. Chama squamosa. Brand. 

 Avicula Bartoniensis*, Wright MS S. Corbula cuspidata. Sow. 

 Balanus. longirostrata. Desk. 



* The new species named in this paper will be described in a fiiture 

 Number of the ' Annals of Nat. History.' 



