132 SILUEIA. [Chap. VII. 
further to be noted that the 4 Macigno,' or young Italian rock, is infinitely 
more hard, compact, and durable than the very ancient stone of Ludlow !* 
Upper Ludlow Eocks at the Bone Well!. (From Sil. Syst. p. 250.) 
The surfaces of these Upper Ludlow rocks are occasionally covered by 
small wavy ridges and furrows, here and there crossed by little, tortuous, 
raised bands; the former of these resulted from the rippling action of 
waves when the sediment was accumulating under a shallow sea, and 
the latter are the traces left by worm-like or other animals on a sandy 
and muddy shore during the intervals of the tides. 
It is chiefly in this upper portion of the formation that the best-defined 
organic remains are found, often preserving the sharpness of their forms, 
and the remains of their original shelly coverings. 
Here we meet with a profusion of the following fossils: — Chonetes lata, 
PL XX. f. 8 j Orthonota amygdalina, PL XXIII. f. 7 ; Goniophora cymbaefor- 
mis, f. 2 ; Pterinea lineatula, f. 16 ; P. retroflexa, f. 17 ; Discina rugata, PL XX. 
f. 1, 2; Orthis elegantula (var. orbicularis), f. 9; O. lunata, f. 11 ; Rhynchonella 
nucula, PL XXII. £ 1, 2 ; Cyclonema corallii, PL XXIV. f. 1 ; C. Octavia, f. 4 ; 
&c. j and the curved shelly Annelide-tube, Serpulites longissimus, PL XVI. f. 1. 
Cornulites serpularius, PL XVI. f. 3-9, and a small Tentaeulite, f. 12, with the 
minute Beyrichia Wilckensiana, PL XXXIV. f. 21, and B. Klcedeni (Foss. 63. 
f. 4), are also not uncommon. 
Corals are rather scarce ; yet Alveolites fibrosus is found frequently incrusting 
particular species of shells, — Cyclonema corallii and Murchisonia corallii, 
PL XXIV. f . 1 & 7, as their names imply, being its favourite habitats. This 
Coral has been figured, p. 119 (Foss. 18. f. 8). 
* See a description of the Tertiary Macigno of Italy, in my Memoir ' on the Alps, Apennines, and 
Carpathians/ Quart. J ourn. Geol. Soc. vol. v. p. 280. 
t This well is so named because bones of mice, frogs, and other small animals are from time to time 
washed out from the open joints (a) of the impending rock. Old Drayton, in his Polyolbion, con- 
sidered this a great marvel, and converted the bones of frogs into those of fishes :— 
" With strange and sundry tales _ - 
Of all their wondrous things; and, not the least in Wales, 
Of that prodigious spring (Trim neighbouring as he past) 
That little Jishes' bones continually doth cant." 
