PLATE 27, 28. 
SHELLS. IRONSTONE. 
P. 27 . — FIG. 1 , 2 . P, 28 . — FIG. 5 . 
CONCHYLIOLITHUS (Myce ovalis*) My^ testd 
ovata, natibus rugosis, (card inis dente primario cre- 
nulato : laterali longitudinali : alterius duplicate.) 
S. p. 
A fossil shell — The original a Mya — Ovate, marked with 
unequal, concentric, transverse, strice. One end somewhat 
pointed, the other rounder. Beaks wrinkled, placed near 
the obtuse end. Hinge (visible only in the recent species) 
furnished, in one valve, with a broad, thick, crenated tooth, 
from the side of which proceeds a single, smooth longitu- 
dinal one — In the other valve the teeth are double, other- 
wise similar in form. 
Found in a solid stratum of ironstone, which extends 
from Tupton-Moor to Stavely. Mr. Whitehurst considers 
this petrifaction, in his “Inquiry into the original State and 
Formation of the Earth," p. 208, to be the remains of the 
* The original of this fossil has been confounded by English authors, with 
the Mya Pictorum of Linn^, to which it is nearly related, though certainly 
a distinct species. It is very common in most of our rivers ; whereas the 
true Mya Pictorum is rare, if indeed it has been ever found, in this country. 
Dr. Pultney appears to be the first English naturalist who noted the difference 
between these two shells. In a part of this work formerly published, we 
had fallen into the same error as others, in supposing the prototype of our 
petrifaction to be the Mya Pictorum. The mistake was obligingly pointed 
out by Mr. Sowerby, to whom we beg leave to return our thanks. 
