202 
DESCRIPTION OF THE FOSSILS. 
but has more lamellae ; also to C. helianthoides xx. 2, but the central hollow is larger, 
and the whole disk more concave. 
C. crenulare. Ph. Pl. II. fig. 27, 28. Clitliero; Mendip ; Bristol; 
Derbyshire. 
Hemispheric or discoid ; stars angular, concave, the limb flat, rising to a thin 
crenulated margin, and sinking to a deep oval cup in the centre, which bears in the 
middle a conical (twisted) umbo, rarely proliferous ; lamellae about 48 ; alternately long 
and short. (It seems analogous to both C. ananas and C. hexagonum Goldfuss, 
but C. hexagonum has equal lamella ?, — ours unequal.) 
C. floriforme. Martin, t. 43, appears to be different from C. crenu- 
lare ; it occurs in Bolland. 
C. basaltiforme. Pit. PI. II. fig. 21, 22. Babble head ; Moughton 
scar; Hesket-Newmarket ; South Wales; Wrekin. 
Composed of adherent prismatic or pyramidal tubes, striated longitudinally, and 
undulated transversely; lamellae 36, 50; the marginal lamellse commencing within 
a thin crenulated vertical dissepiment. (Lithostrotion striatum, Park. Flem.) 
Hydnopoka ? — cyclostoma. Ph. PL II. fig- 9, 10. Northum- 
berland. 
Inerusting shells ; all the exposed surfaces covered with vermicular ridges, or 
insulated points : in the large circular cells they form radiating lines (magnified in 
fig. 10.) 
LithodeNdron. — I n lower scar and Yoredale limestones. All the 
species have concave cells, and a prominent central umbo or axis, (gene- 
rally oval in the section) the lamella; are generally twisted or extinct 
near the centre. 
L. sexdecimale. Ph. Pl. II. fig. 11, 12, 13. Kirby Lonsdale, Ket- 
tle well ; Penyghent ; Aldstone moor ; Northumberland; Veynal. 
External tube thick, t ' (1 inch diam. ; medial lamella;, 15 or 16 ; arched vertical 
dissepiments. — The external tube sometimes is, sometimes not striated. 
L. irregulare. Ph. Pl. II. fig. 14, 15. Ash fell ; Northumberland, &c. 
External tubes thick, ^ inch diam., often coalescing ; medial lamellae 18, 20 ; three 
of these usually united in a singular manner ; marginal lamellae rudimentary. (Org. 
Rem. vi. 3 and 7-) 
L. fasciculatum. Ph. Pl. II. fig. 16, 17- Ribblesdale ; Teesdale; 
Ash fell ; Bristol ; Northumberland. 
External tube flexuous, striated; }—}■ of an inch diameter; an internal tube 
uniting the lamellae, 24 to 26 within, 48 to 52 without. Mad. caespitosa Martin, 
