ij6 Appendix to Pari I. 



PALEOZOIC SHELLS FR03I VAN PIEMEN'S LAND, 



EEFEEEFJ) TO AT P. 155 OP THIS VOLUilE. 



1. Peoducta ET7GATA. 



This is probably the same species with that named Produnta 

 rugata by Phillips (•' Geology of Yorkshire/ part ii. plate vii. f. 16): 

 it is, however, in too imperfect a condition to allow me to decide 

 positively. 



2. Peodtjcta BEACHTTHJEErs. G. Soicerby. 



Product a, Testa subtrapeziformi, compressd, parte anticd latiori, sub- 

 bilobd, posticd angustiori, lined cardinali brevi. 



The most remarkable characters of this species are the shortness 

 of the hin^e-line, and the comparative width of the anterior part: 

 its outside is ornamented with small, blunt tubercles, irregularly 

 placed : it. is in limestone, of the ordinary grey colour of mountain 

 limestone. Another specimen which I suppose to be an impression 

 of the inside of the flat valve, is in stone, of a light rusty-brown 

 colour. Tbere is a third specimen, which I believe to be the im- 

 pression of the inside of the deeper valve, in a nearly similar stone, 

 accompanied by other shells. 



1. Spieifera spbeabtata. G. Sowerby. 



Spirifera, Testa Icevissimd, parte mediand lata, radiis lateralibus 

 utriusque later is paueis, inconspicuis. 



The breadth of this shell is rather greater than its length. The 

 rays of the lateral surfaces are very few and indistinct, and the 

 medial lobe is uncommonly large and wide. 



2. Spieipeea eotuxdata ? Phillips's ' Geology of Yorkshire,' 



pi. ix. f. 17. 



Although this shell is not exactly like the figure above referred 

 to, it would perhaps be impossible to find any good distinguishing 

 character. Our specimen is much distorted : it is, moreover, an 

 example of that sort of accidental variation that shows how little 

 dependence, ought, in some instances, to be placed upon particular 

 characters ; for the radiating ribs of one side of one valve are much 

 more numerous and closer than those on the other side of the same 

 valve. 



