THE OLD RED SANDSTONE SYSTEM. 



68' 



which furrows diverge, cover the head. The thin angular body is apparently, though 

 not really, composed of joints like the trilobites, to which family the creature was 

 at first referred; and, in fact, it seems a link between the crustaceans and fishes. 

 The scales of the head magnified are represented in the engraving. 

 "Has the reader ever seen a saddler's cutting-knife a tool 

 with a crescent-shaped blade, and the handle fixed transversely 

 in the centre of its concave side? In general outline the Cepha- 

 laspis resembled this tool ; the crescent-shaped blade representing 

 the head, the transverse . handle the body." It seems to have 

 been well prepared for defence, encased in armour of great strength, for its remains 



are found very perfect in strata 

 impregnated with iron, in which 

 few fossils could have survived. 

 It would have been likewise a for- 

 midable animal for attack, could 

 it have commanded any consider- 

 able impetus, like the sword-fish, 

 the sharp margin of the shield 

 doing the work of a vigorously 

 hurled javelin. This singular 

 ichthyolite is the characteristic 

 organism of the cornstone part of 

 the sandstone system, both in England and Scot- 

 land. The several species which occur in the 

 border English counties, says Mr. Murchison, 

 " seem not to have been suddenly killed and en- 

 tombed, but to have been long exposed to de- 

 structive submarine agencies, such as the attacks 

 of animals, currents, and concretionary action, by 

 which they were dismembered." Though hun- 

 dreds of fragments have been found in England, it 

 is remarkable, that no example of an entire fish 

 has yet been discovered. This is not the case 

 with Scotland, where the species Cephalaspis 

 Lyellii was found entire in Forfarshire, and named 

 by Agassiz after the distinguished geologist born 

 in that county. 



Coccosteus. This has been styled a Cephalaspis 

 a stage further on, more of a fish, having the horns 

 of the crescent-shaped head cut off", and the an- 

 gular body terminated by a long vertebrated tail. 

 The name, bone-berry, refers to berry-like tuber- 

 cles, with which the plates composing its bony 

 casement are dotted. The creature has been aptly 

 compared to a boy's kite, varying in length from 

 one to two feet. Four species have been described, 

 of one of which this is a representation. Their fragments 

 are frequently of a brilliant blue or purple colour, and 

 are easily recognised from the contrast with the dull red 

 tint of the sandstone rock. Mr. Murchison supposes the 



