FROM THE RED CHALK. 165 



" From this part of the Carstone I have obtained Perna Mulleti, Ancyloceras gigas, 

 Pteurotomaria gigantea — fossils which, viewed in connection with the presence of Ammo- 

 nites Deshayesi, &c, correlate the portion of the Carstone immediately above the clay (z) 

 with the base of the English Lower Greensand. 



" By a reference to the section it will be seen that the Hunstanton Red Chalk is, in 

 position, lower than the Chalk-marl {a), and higher than the Lower Greensand (x, y) ; 

 the fossils also, it will be observed, recorded in the list as common to the bed, present a 

 mixture of what are generally considered Lower Chalk, Upper Greensand, and Gault 

 forms. The mingling together of these species, no less than the peculiar aspect of the 

 stratum, has long caused the Red Chalk to be a fertile field for discussion in reference to 

 its proper position in the geological scale, various writers offering various opinions, Mr. 

 C. B. Rose 1 inclining to its being the equivalent of the Gault, Mr. H. Seeley 2 to its being 

 Upper Greensand, and Mr. Judd 3 to its combining both formations. If, however, the 

 very fine section of the Gault at Folkstone (where the succession of the beds and their 

 fossils can be examined in situ) be taken as typical of the English Gault, then it will 

 become evident that the ' Red Chalk ' is the representative of the upper division of that 

 formation." 



Genus — Goniophorus, Jgassiz, 1838. 

 Goniophorus, Desor. Goniophorus, Cotteau. 



Test small, circular, elevated above, and flat beneath. Interambulacral areas wide, two 

 rows of large tubercles with well-developed areolae, crenulated bosses and imperforate 

 mammelons ; pores small, simple, unigeminal. Ambulacral areas very narrow, and having 

 the poriferous zones slightly undulated. 



Mouth-opening small, peristome decagonal, with nearly equal sized oral lobes. 



Apical disc smooth, prominent, regularly pentagonal, and moderately large, composed 

 of five ovarial and five ocular plates, and one suranal placed before the vent, which is 

 excentral, in the axis of the body, and placed a little backwards, as in the genus Peltastes. 

 The disc is destitute of sutural impressions so characteristic of many Salenid^;, and is 

 ornamented with prominent carinas, which assume regular geometrical figures, altogether 

 independent of the form of the ovarial plates or their connecting sutures ; in fact, it is 



' " On the Geology of West Norfolk," ' Phil. Mag.,' 1835, vol. vii, p. 180. 



2 "Notice of Opinions on the Stratigraphical Position of the Red Limestone," 'Ann. Mag. Nat. Hist.,' 

 1861, vol. vii, p. 240. 



3 " Strata which form the base of the Lincolnshire Wolds," ' Quart. Journ. Geol. Soc.,' vol. xxii, 

 p. 249, 1867. 



