﻿CRETACEOUS BRACHIOPODA. 



21 



Wc must now hasten to point out some important general modifications to be effected 

 to the published portion of our Monograph. 



It is stated at p. 107 that, "according to the generality of British geologists, the 

 Faringdon Sponge-gravel would belong to the age of the Lower Greensand, by myself to 

 that of the Upper Greensand or Tourtia, and by Mr. Sharpe to the Upper Maestricht 

 beds." It now appears from the minute and able investigations by Mr. Meyer 

 that the generality of British geologists were correct, and that both Mr. Sharpe and 

 myself were mistaken. Consequently all the species described by myself in 1852 and 

 1855, from the " Sponge-gravel " of Faringclon, will have to be considered of the age of the 

 Lower Greensand. What misled me was finding in the Sponge-gravel above named so 

 many of the Tourtia forms, and the Tourtia having been considered by several foreign 

 geologists to be newer than the Gault ; and, indeed, the exact geological position of that 

 Belgian deposit seems still to remain an open question. 



The Speeton Clay had also been placed above the Gault, while it has since been shown 

 by Mr. Judd to be older than that formation. 



The important discovery of the Upware and Potton beds, and their numerous Brachio- 

 poda, by Messrs. Walker, Seeley, Keeping, Earwaker, and others, as well as of the Tealby 

 series by Mr. Judd, and the important investigations among the Cretaceous deposits of 

 the south-east and west of England by Mr. Meyer and Mr. R. Lankester, in addition to 

 those by Mr. R. Tate in Ireland, have brought to light many species unknown when I 

 published my Monograph, and which will necessitate a somewhat lengthened Supplement. 



Messrs. Meyer, Walker, Judd, R. Tate, and several others to be named in the 

 sequel, have afforded me much assistance and information, for which I now beg to 

 tender them my warmest acknowledgment. 



Mr. Judd's important discovery of Upper Greensand and Chalk-with-flints in the 

 Isle of Mull is one of the most recent additions to our knowledge. Few Brachiopoda, 

 however, have been detected in the Cretaceous rocks of Scotland, some are quoted by 

 Messrs. Salter and Ferguson from the drifted Chalk-flints of Aberdeenshire, Crania 

 costata, Sow., Tcrebratula, sp., Kingena lima, Defr., Bhgnchonella Mantelliana, Sow. ; 

 and llh. compressa, Lam., from the Upper Greensand of Moreseat, in the same county; 

 ' Quart. Jour. Geol. Soc.,' vol. xiii, p. 85. 



1. Lingxjla truncata, Sow. Dav., Cret. Mon., PI. I, figs. 27, 28, and 31. 



Nothing new. Specimens from Lower Greensand of Shanklin, Hythe, Pease- 

 marsh, Faringdon (Meyer). 



2. Lingula sub-ovalis, Dav. Cret. Mon., PI. I, figs. 29, 30. 

 Nothing new. It seems to be rare. 



