1880.] NATURAL SCIENCES OF PHILADELPmA. 369 



Pecten Poulsoni, Morton (Synopsis Org. Rem. Cret. Group, p. 59), a companion of 

 Orbitoiden Mant-Ui, Mort. sp., and, according to Ililgard, an enseutialli/ Vicks- 

 burg (Oligoeene) fossil. Wood's Bhiff. 



Cancellaria evulsa, Sowerby [rjuccinum evulaum, Brander] (Miner. Conchol., iv, p. 

 84), from tlie Barton clay (Upper Eocene) of England, and Grignon ("Calcaira 

 grossier") of France. i Wood's Bluff. 



Pleurotoma (Cochlespira) cristata, Conr. (J. A. N. S., 2d ser. i, p. 115), originally 

 described from the Vicksburg group, but doubtful whether differing from the 

 Pleurotoma bella, Conr., from the Upper Eocene of Texas. Wood's Bluff. 



In addition to the above, tliere is among the fossils from Wood's 

 Bluff an immature Gardium (Protocardia)^ which may possibly 

 represent the young of C. Nicolleti (Jackson group), with which 

 it agrees in outline and general ornamentation, or that of G. Vir- 

 giniana, Conr. (Pamunkey River), an undescribed species, but of 

 vrhich a labeled specimen is in the collections of the Academy. 

 The absence of asperulations on the posterior slope of the speci- 

 men in question, however, rendering it uncertain whether they 

 were ever present, or whether they are merely abraded or water- 

 worn, allows of no absolute specific determination. 



Whatever ma}' be the palseontological facies of the deposits in 

 question, however, there can be no reasonable doubt as to their 

 true position, since Dr. Smith, as he informs me, has traced bed 

 No. 6 (or the uppermost bed immediately underlying the stratified 

 drift) of his Wood's Bluff section to the mouth of Witch Creek, 

 about 2 miles below on the Tombigbee River, where its relation to 

 the overlying " Buhrstone " is made manifest in an exposure just 

 beyond the mouth of the creek. White Bluff, about 250 to 275 

 feet in height, beautifully exhibits the white siliceous clay stones 

 and silicified shells so characteristic of the southern Buhrstone 

 formation. These occupy the uppermost portion of the l)luti', and 

 make up fully 100 feet of its vertical height; the intermediate 

 portion extending to the water's level, is mainly composed of 

 laminated lignitic clays, with occasional intercalated beds of pure 

 lignite. It becomes manifest from what has just been stated that 

 the fossiliferous beds of Wood's Bluff {et conseq. the equivalent 

 deposits on Knight's and Cave Branches and Bashia Creek) must 

 be between 150 and 200 feet below the base of the Buhrstone 



' A very closely allied species, the Tritoniuvi{!) jiaucivaricatum of Gabb, 

 occurs in the Tejon group (Upper Cretaceous — Eocene?) of California, 

 associated with C'nrdita planicosta. and other characteristic forms of Ter- 

 tiary fossils. 



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