ON CRETACEOUS POLTZOA. 307 



presence of these two iron-stained bands was indicative of the position 

 where the Polyzoan fauna might be found ; but in some of the pits the 

 hands were either too high or too low, or, in other words, this zonal 

 division was not a marked feature in the rocks exposed, and the yield of 

 forms consequently suffered. Nearly the whole of the Polyzoa sent tp me 

 were derived from one particular pit, but similar forms, though not so 

 abundant, are found in other pits whenever the sectional or zonal lines 

 indicated above were exposed. After passing a little section which yielded 

 a few Polyzoan fragments, the Luton valley widens, the escarpment is 

 not so deep, and the Polyzoa zone is lost under the bed of the valley, 

 where it is not possible to meet it again except by boring. Mr. Gamble 

 says it must not be supposed that the Polyzoa are wholly confined to the 

 zone which is bracketed in the sketch. Polyzoa will be, and have been, 

 found both above and below the iron-stained bands ; but the greater 

 number are really found in the division or zone indicated.' 



IV. CATALOaUE OF POLTZOA FOUND IN THE CHATHAM ChALK. 

 (With full references to d'Orbigny and others). 



Sub-order Ctclostomata. ^ 



1825. Genus Stomatopoea (Uniserial), Bronn, d'Orb., ' Terr. 



Cret.,' p. 833. 



1. Stomatopora Cixoni, sp. n. (=AIecto gracilis, Lonsd., 'Foss. 



Sussex,' p. 269, pi. 18a, figs. 1-lc). 



This is not the Aledo gracilis of either Edwards or Bronn (see d'Orb., 

 ' Terr. Cret.,' p. 843, pi. 758, figs. 17, 18) ; but, as the form is abundant iu 

 the Chatham Chalk, 1 have thought it best to rename Lonsdale's species. 



2. Stomatopora ramea, Blainv. ('Terr. Cret.,' p. 842, pi. C30, fig. 12, 



non Synonyms of d'Orb.). 



3. „ granulata, Edw., var. gigantea, Perg., ' Revis. des 



Bryoz.,' p. 330. 



4. „ gracilis, Edw., ' Ann. des Sc. Nat.,' 9, p. 207 (see 



d'Orb., 'Terr. Cret.,' p. 843). 



1826. Genus Peoboscina, Audouin (d'Orb., 'Terr. Cret.,' p. 844). 



5. Proboscina cornucopige, d'Orb., ' Terr. Cret.,' p. 855, pi. 634, 



figs. 7-9. 



6. ,, cornucopias, var. eximia, var. n. (near P. echinortim, 



d'Orb.), only more delicate (see pi. 633, fig. 12). 



7. „ elevata, d'Orb. var. (allied to Beptotubigera id., 



d'Orb., I. c, p. 755, pi. 760, figs. 1-3). 



8. „ Wetherelli, Morris (=I)iastopora, Lonsd., ' Foss. Sus.,' 



pi. 18a, fig. .3). 



9. „ ramosa, Michelin, Diastopora, Lonsd., ' Foss. Sus.,' pi. 



18b, figs. 1-lb. 



' Since this was written I have collected material from other pits for the purpose 

 of comparison, and I can verify Mr. Gamble's remarks. • 



z 2 



