CONTRIBUTION TO THE PALEONTOLOGY OF TRINIDAD. 91 

 Locality.— Along the shore 700 feet east of the pier at Brighton, Trinidad in 



an impure asphalt. 



Geological horizon.— Upper Oligocene, about equivalent to the Chipolan stage 

 of Florida. 



Cerithium isabellse new species. Plate XII, Figure 19. 



Description.— Shell short and broad, conic, with a rather obtuse spire; whorl 

 about five, of which the penultimate is ornamented with three spirafrows of 

 bead-like nodules, with sets of three (less frequently two) revolving spiral threads 

 intervening between the rows of beads; last volution also with three main rows 

 of nodules with intervening sets of spiral threads, this ornamentation being 

 continued more or less obsoletely towards the base of the shell; varices apparently 

 not developed (shell partially concealed by the matrix). 



Height 16, greatest width 8 mm. 



Remarks.— This shell resembles in form and sculpture C. webbi Harris from 

 the Lower Claiborne Eocene of Texas. It is an interesting fact that three species 

 of Cerithium described in this report (C. soldadense, C. karrisii, and C. Isabella), 

 should resemble the Texan shell, and be quite unlike any figured from Florida. 



This species can be distinguished from the closely related form, C. karrisii, 



by its much broader proportions, greater number of spiral threads, and absence 

 of varices. 



Locality.— Along the shore 700 feet east of the pier at Brighton, Trinidad, in 

 an impure asphalt. 



Geological horizon.— Oligocene. About equivalent to the Chipolan stage of 

 Florida. 



Cerithi 



XII 



Description. — Shell small, convex, number of whorls not known; transverse 

 sculpture of narrow, curving, rather irregular, plications, present chiefly on the 

 penultimate volution; spiral sculpture of revolving beaded threads alternating 

 with finer beaded lines ; on the body whorl there are two or three of the coarser 

 beaded threads, and then a fine row of beads just below the suture. 



Diameter of last whorl 4 mm. 



Remarks. — This species has no resemblance to any described from the Midway 

 of the southern States, nor has it been found in the Maria Farinha beds of Brazil. 

 Its closest affinity in general form and type of sculpture is C. webbi Harris 70 

 from the Lower Claiborne Eocene of Texas. 



Locality.— Bed No. 2, Soldado Rock, near the Serpent's Mouth, in the Gulf 

 of Pari a. 



Geological horizon.— Midway Eocene. Equivalent to the Midway of Alabama 

 and that of the Rio Maria Farinha Beds, State of Pernambuco, Brazil. 



" Proc. Acad. Nat. Sci. Phila., p. 79, pi. 9, fig. 3, 1895. 



