72 G. F. Matthew — Great Welsh Paradoxides. 



3. If the Jacksonian were younger than the Claibornian, the 

 Highest Claibornian ought to be more nearly related to it than 

 the Lowest. I found, on the contrary, the fauna of the latter 

 more similar to the Jacksonian. For instance, Lunidites inter- 

 stitia Lea is common in Jackson, not rare in the Lowest Clai- 

 bornian, very rare in the Highest. Mitra paciilis var. dumosa 

 is common in Jackson ; M. paciilis is rarer in the Lowest Clai- 

 bornian, and apparently absent in the Highest. 



4. If Jackson were older than Vicksburg, the Lower Vicks- 

 burgian ought to show more relationship to it than the Higher. 

 I found rather the contrary ; for instance, Astarte parva Lea, 

 in the lowest stratum, is more different from the Jackson form 

 than in the highest stratum. 



5. As a proof of this succession and derivation, the following 

 facts are to be considered : Venericardia rotunda Lea in its 

 young form resembles the allied Jacksonian species. Fulgur 

 filius Meyer repeats in its sculpture Fulgur Mississippiensis Conr. 



Tellina Vicksburg ensis Conr. resembles the young form of the 

 allied variety in Jackson (pee part I, Nos 22, 69, 35). 



6. Among the fossils from Wood's Bluff, Ala., which I 

 received, there is a Vicksburgian species (Pleuroloma terebralis 

 Lam. var. carinata Conr.), a Jacksonian species (Actoeon, sp.), 

 but no characteristic Claibornian species. According to the 

 determinations of Professor Heilprin, moreover, Natica Missis- 

 sippiensis Conr. and Pecten Poulsoni Mort. occur in these strata, 

 so that they show a decidedly Vicksburgian character. Accord- 

 ing to Professor E. A. Smith they are stratigraphically far 

 below the Clabornian. 



7. In Harper's Geology of Mississippi (Jackson, 1857, p. 141), 

 a bluff in "Wayne County is described and extensively figured. 

 Harper's stratum on the top b, "containing Pectens of several 

 species, Gallerites and several Ostrese," is apparently my stratum 

 b from Claiborne, which I showed to occur near the surface at 

 Enterprise, a place not very distant from this locality. Har- 

 per's second stratum below, called d, "filled with Orbitoides, 

 Ostrea, Pecten of several species, Area, Flabellum, Cardita, 

 Gallerites, etc.," seems to be of Jacksonian or Vicksburgian 

 character. 



Art. XI. — On the probable occurrence of the Great Welsh Para- 

 doxides, P. Davidis, in America ; by Geo. F. Matthew. 



This, the largest and most remarkable species of Paradox- 

 ides occurring in the Primordial fauna of Europe, has not, so 

 far as the writer is aware, been hitherto found in America. It 



