69 
AMMONITES Planorbis. 
TAB. CCCCXLVIIL 
Spec. Char. Discoid, smooth; whorls three 
or four, two thirds exposed. 
Few shells are more plain in their appearance than this 
unornamented Ammonite, for its situation and analogy to 
the following leave no doubt of its being an Ammonite, 
although we have not met with the septae. It is always 
found so much flattened that little can be added to the 
specific description, for its thickness and the form of the 
whorl cannot be ascertained ; we can only see that the 
whorls encrease rather rapidly in diameter, that they 
have no radii or tubercles, and that the striae of growth 
are very fine. The inside pearly coat is nearly all that is 
preserved, and that is sometimes very highly iridescent. 
Not of very rare occurrence in a kind of slaty Clay 
belonging to the Lyas beds, at Watchet. Fig. 1 is from 
that locality. 
Fig. 2 is taken from, a high coloured individual said 
to be from Lincolnshire, placed in Mr. Sowerby’s cabinet, 
by the Rev. R. B. Franciss. 
