684 



GEOLOGY. 



fossils ; but upon a more careful attention being paid to it, they were discovered in 

 abundance, and of singularly interesting and important forms. The remains of vege- 

 tables, though numerous, are yet very indistinct and much broken, as if they had been 

 drifted by powerful currents from a considerable distance. Descending into the quarries 

 of the parish of Carmylie in Scotland, in the cornstone formation of the system, 

 Mr. Miller found almost every layer of the strata covered with carbonaceous markings 

 irregularly grooved stems, branching out into boughs at acute angles, seeming minia- 

 ture semblances of the trunks of gnarled oaks and elms; also oblong leaf-like impres- 

 sions, with impressions of more slender form, like the narrow parallel-edged leaves of the 

 sea-grass weed ; and a large bunch of riband-like leaflets converging into a short stem, the 

 -whole resembling a scourge of cords. The engraving shows some examples. In the same 



Vegetable Remains in Old Red Sandstone. 



locality the same observer found irregularly-shaped patches, reticulated into the resem* 

 blance of polygonal meshes, like pieces of ill-woven lace, familiarly called by the work- 

 men " puddock spawn," from their similarity to the eggs of the frog. These patches are 

 supposed by Mr. Lyell to be formed of remains of the eggs of some gasteropodous mollusc 

 of the period. Shells are abundant in the lower part of the system in England, several of 

 which have been carefully figured by Mr. Murchison, and in Scotland the traces or 

 remains of gigantic crustaceans are of common occurrence. The labourers in the sand- 

 stone of Forfarshire have long remarked appearances in the strata, denominated by 

 them " petrified seraphims," from an imaginary resemblance to the representations of those 

 angelic beings upon the gravestones in country churchyards* A number of detached 

 fragments having been discovered at Bulruddery, were submitted to the inspection of 

 M. Agassiz in Edinburgh, in the presence of other geologists, whom they had completely 

 puzzled. "I will tell you," he observed, after a short examination, " I will tell you 

 what these are the remains of a large lobster." The distinguished ichthyologist then 

 took fragment after fragment from the group, arranged the parts, exhibited the animal to 

 the company a huge lobster, indicating a total length of four feet. 



Ichthyolites, or fossil fishes, belonging to the vertebrated order$ are, however, the cha- 

 racteristic fossils of the system, some of which appear to be organisations but a little 

 removed from the humbler crustaceans, while others display the most perfect structure. 

 Having now arrived at an era in the history of the globe which furnishes decisive and 

 abundant evidence of the prevalence of high organic life in the waters^ the state of ichthy- 

 ology, which has undergone a complete revolution in our own day, and of fossil ichthy- 

 ology, requires a notice. The number of living species of fishes at present known 

 amounts to somewhat more than 8000. It was formerly usual to classify fishes according 

 to the nature of the skeleton, into the two great groups of osseous or bony, and 

 cartilaginous. The osseous class embraces those \vhose skeletons are the most durable, 

 being composed of calcareous earth pervading an organic base : the cartilaginous^ on the 

 contrary, contain little of this earth, the skeleton consisting of elastic, semi-transparent, 

 indurated animal matter, speedily yielding to decay. But Agassiz, departing from this 

 arrangement of Cuvier, distinguishes four great orders of fishes, characterised by 



| essential differences in the form and structure of the scales, or the dermal (skin) system, 



I 



