STRATIGRAPHICAL DISTRIBUTION. 113 



characteristic and beautiful fossils of the series, is totally barren of them • I never knew of 

 the occurrence of the least trace of a Brachiopod for the first hundred and fifty feet as we 

 ascend, except in the five or six feet of Perna bed at the base. In the upper beds, to the 

 depth of more than 200 feet, nearly 300 perhaps, there is a great dearth of fossils of any 

 description ; I have, however, obtained a specimen of Bh. Gibbsiana from the uppermost 

 portion. The nodular beds of Horseledge and Black Gang Chine present a very curious 

 analogy with the Cracker nodules, in the repetition of ferruginous casts of those fossils 

 which we saw in the latter as delicate shells, and which in very many instances do not 

 seem to appear between these points in the series, a distance of perhaps 500 feet. Now, 

 the Horseledge or Yellow Ledge beds contain Lingula truncata, Ter. cettica, T. tamarindus, 

 T. sella, and Bit. parvirostris, while the Crackers are apparently deficient of these species." 



It is, therefore, evident that the Lower Green Sand in England contains the 

 minimum, and not the maximum of species. 



The Gault and its dependencies dispose but of few species of Brachiopoda, and these 

 no where numerically abundant, and, with the exception of T. sella, appear specifically 

 different from those common to the Lower Green Sand. 



The following is a list of the forms I have hitherto been able to examine : 



1 . Terebratulina striata, Wahl., var. pentagonalis, Phillips. One example from the Speeton 



Clay. 



2. „ gracilis, Schl., var. Common, according to Mr. C. B. Rose, in the Blue 



Gault of West Norfolk. 



3. Terebratula capillata ? D'Archiac (rare). Three or four examples from the Bed Chalk of 



Hunstanton Cliffs (Norfolk). 



4. ,, biplicata, var. Sow. Occasionally met with, but nowhere abundantly, in the 



Speeton Clay, Gault, and Bed Chalk. 



5. ,, sella, Sow. (very rare). In the Gault near Maidstone. 



6. „ semiglobosa, Sow., var. subundata (rare). In the Bed Chalk; 1 and this 



appears to be the first appearance of the species which 

 continues to be represented in each successive deposit up 

 to the Chalk. 



7. Bhynchonella sulcata, Parkinson. A few rare examples from the Speeton Clay and Gaidt. 



8. „ lineolata, Phillips, sp. A single specimen from the Speeton Clay of Yorkshire. 

 Over the Gault, in natural succession, we arrive at a very variable series of sandy and 



marly beds, with occasional bands of limestone, known under the appellations of Upper 

 Green Sand, Chloritic Marl, Tourtia and Craie et Sables Chlorites by the French; and it is 

 in the direct succession or equivalents in different localities of the layers forming this 

 series of beds, between the Gault and the Chalk Marl, that some further investigation 



1 Mr. C. B. Rose states that the red bed, (improperly called Chalk), occupies the place of the Gault 

 lying immediately upon the Lower Green Sand ; the fossils are similar to those met with in other Gault 

 districts (see 'Ed. Phil. Journal,' Nov. and Dec. 1835, and Jan. 1836) : at Hunstanton Cliff the red bed 

 measures about 3 feet 10 inches. 



