760 



THE WONDERS OF GEOLOGY. Lect. MIL 



Calymene (Lig?i. 178) is a common form; and a very pecu- 

 liar modification of this family, termed Brontes* has 

 hitherto been found only in the Devonian deposits. 



Murypterus.^ A large species of this extinct genus of 

 crustaceans occurs in the Devonian sandstone of Forfarshire ; 

 and fragments of the case or shell have long been known 

 to collectors as " jjetrified Seraphims" the name applied to 

 these fossils by the quarrymen, from their fancied resem- 

 blance to the conventional figures of cherubs. The first 

 specimens which threw light on the nature of the original 

 were discovered by Mr. Miller at Balruddery. The cara- 

 pace of this animal forms a lozenge-shaped shield, and the 

 appendage of the post-abdomen is a continuous flap. The 

 claws resemble those of the common lobster. The crus- 

 taceous covering, or shell, is ornamented externally with 

 circular and elliptical markings, which give it an imbricated 

 or scaly appearance : and it was the imprints of this sur- 

 face that produced the enigmatical fossils to which the 

 workmen ascribed a celestial origin ! Some specimens in- 

 dicate a total length of four feet .J 



9. Fishes of the Devonian System. — M. Agassiz 

 has determined no less than one hundred species of fossil 

 fishes from the Devonian formation, in which, but twenty 

 years since, a few doubtful scales discovered in Forfarshire 

 by Dr. Fleming, w^ere the only known vestiges of this class 

 of vertebrated animals. In the British series, there are 

 upwards of sixty species, belonging to twenty-six genera. § 

 Of these, the most characteristic are the Cephalaspis, 

 Pterichthys, and Coccosteus, which form a group of ex- 

 tinct genera, that has no representatives in the Silurian 



* Medals of Creation, p. 559. f Ibid. p. 541. 



X See New Walks in an Old Field, p. 147. There are specimens 

 of this crustacean in the British Museum from the quarries of 

 Carmylie. 



§ See Mr. Tennant's Stratigraphioal List of British Fossils, p. 111). 



