NOTES, 
42 
The Eutrochal Limestone of Derbyshire has its name from portions 
of the same column being imbedded therein,—When the Entrochite 
is absorbed, the cast is denominated Screw-stone. 
Star Stones. — Single joints of the Pentacrinital column are so 
called ; they are particularly abundant in the Cliffs of Lyme and 
Charmouth, Dorsetshire.— Org. Rem , vol. ii. tab. 13. 
Echinidce.— Silicious casts of some of the Genera of this Order 
are exceedingly interesting; these principally occur in the flints of 
Diluvial Gravel, and are generally known by the name of Fairies’ 
Stones. The Cidaris corollaris of Parkinson (Org. Rem. vol. iii. 
tab. 1, fig. 7,) is a flint cast of Echinus saxatilis (tab. 3, fig. 1). 
Echinital Spines are confined to the two Genera, Echinus and 
Cidaris ; those belonging to the first, being attached to the epidermis 
or external covering only, are small and acicular, and belong to 
E. germinans of the Bath Oolite and E. Konigi of the Chalk. The 
spines of Cidari are attached to the papillae by an internal muscle, 
and are of considerable size. C. papillata of the Coral Rag are 
clavate; they are the Lapides Judaici and Petrified Olives of the 
early writers. Murieated and Cucumerine spines are tolerably abun¬ 
dant in the Hard Chalk ; they belong to a variety of C. papillata. 
Insects .—Lhwyd, in his Lythophylacii, tab. 4, has figured four in¬ 
sects from the Coal Shale; these are copied by Parkinson, in his 
Organic Remains , vol iii. tab. 17, fig. 3. Remains of Coleopterous 
Insects occur in the Stonesfield Slate, but I am not aware that any 
figures of them are published. Insects are sometimes found in the 
clear Amber of our Eastern Coast; they belong mostly to the order 
Diptera. 
Pholas. —In the Mud Cliffs (as they are locally termed) of the 
Norfolk Coast, are found casts of the Cavities formed by the Pholas; 
one in the possession of the Rev. James Layton, of Catfield, is three 
inches long, and five inches in circumference ; one side is broken 
away, by which the shell is discoverable, which appears to be allied 
to P. crispatus; this is the largest specimen I have seen. 
Trigonia. —Casts of Trigonia abound in the Portland Oolite, to 
the great loss of the mason and waste of the stone ; they are locally 
termed Horse-heads.— Org. Rem. vol. iii. tab 12, fig. 12. 
Inoceramus. —Shells of fibrous texture, as Inocerami and Belem- 
nites, have been subject to the perforations of minute insects and 
