256 H. IF. Shimer — Fossiliferous Miocene Bowlders. 



Yermetus virginicus (Conrad). C. Diameter of tubes 2'5 mm . 

 Surface with only concentric wrinkles and growth lines. 

 Cerithium sp. r. 

 Cerithiopsis cf. calvertensis Martin. It. 



The fauna of this Block Island bowlder is most closely 

 related to the Lower Miocene, the Calvert, of Maryland. Com- 

 pared with other Tertiary occurrences in this part of New 

 England the fauna is unique. It is entirely different from the 

 fauna of the Eocene bowlders found first by Warren Upham 

 and later by Professor Crosby and others upon the beach and 

 in the glacial till of the bluff at Truro, Massachusetts. It is 

 specifically distinct from the Eocene fauna found by Hoi lick 

 and figured by T. C. Brown* from the ironstone concretions of 

 Chappaquiddick Island, Martha's Vineyard. It contains noth- 

 ing in common with the Upper Miocene fauna of Gay Head, 

 Martha's Vineyard, as listed by Dall,f nor with the Pliocene 

 forms found by Wood worth in the same region.;}; Likewise it 

 is entirely distinct, both lithologically and faunally, from the 

 Miocene phosphatic pebbles found by Woodworth on the 

 south shore of Block Island, and subsequently ascertained to 

 have been " derived from the wreck of a vessel loaded with 

 phosphate rock from the east bank of the Ashley River, S. C."§ 

 It also has nothing in common with the small fauna from near 

 Southampton, Long Island, identified by Gratacap as Pliocene. || 



Considering the possibility of the transportation of bowlders 

 as ballast, etc. from place to place, it may be well to hesitate 

 for further light, such as finding similar bowlders in the till, 

 before assigning this bowlder definitely to a parent ledge in 

 New England. 



Another bowlder, slightly smaller than the preceding, was 

 found by Mr. John E. Tourgee upon the beach at the extreme 

 northern end of Block Island. This hard sandstone bowlder 

 is also highly fossiliferous but the fossils are usually merely 

 external and internal molds and difficult of identification. The 

 most abundant form is identified as Pecten cf. jeffersonius 

 edgecombensis (Conrad). It is one-half as large as that variety. 

 Another abundant form is probably the same as the oyster in 

 the other bowlder, Ostrea cf. sellseformis thomasii (Conrad). 



Massachusetts Institute of Technology. 



*This Journal (4), xx, 229. 

 f Ibid. (3), xlviii, 297. 

 JLoc. cit., p. 229. 

 $ This Journal (3), xlviii, 300. 

 I Nautilus, xxviii, p. 85. 



