MACKIE — FIRST TRACES OF THE SUCCESSION OF LIFE. 
423 
varied : chiselled, ribbed, striated, and cancellated with every kind 
and description of line, groove, and ridge, their markings are only 
exceeded in their diversity by the infinity of the vivid hues and 
curious designs of their beautiful paintings. 
The pearly lustre and nacreous prismatic tints may have vanished 
from the remains of those soft-bodied inhabitants of the fossil shells, 
but the beauty of their forms and the delicacy of their markings are 
truly preserved by Nature's unerring hand in the crystalline marble 
into which their shells in the lapse of ages have been turned. Sunk 
into pits, or attached to protuberances, smooth, or interlocking, even 
that most primitive of all attachments, the ligamental hinge, is never 
alike in two species, is never repeated, as though infinite change was 
part of the great scheme of creation, an attribute of the Deity, to 
be manifested alike in pleasure or pain, in the world or the universe, 
and in the grandest, or most trivial and simple of things. 
The Lingula) of North Wales were first discovered by Mr. Davis, 
in 1845, near Tremadoc, and in the same Lower Silurian beds are 
Lign. 7.— Olbntjs Micbubus 
(nat. size) . From the flffuro 
in the " Decades of the 
Geological Survey," No. u., 
plate ix. From a specimen 
from Trawsfynydd, Meri- 
onethshire. 
associated the remains of several species of trilobites, namely, Olenns 
micrurus, Agnoshis pisiformis, and a Paradoxides, supposed by 
Lign. 8. — Agnostus pisipohmis. 
From Angehn's " Palaeonto- 
logia Suecica," pt. i., 1852, tab. 
vi., fig. 7. [Syn.: EntomoUthus 
paradoxus var. pisiformis. 
Linnteus Iter. Scan., p. 122. 
Syst. Nat., ed. xvi., vol. iii., 
p. 160.J 
