758 



THE WONDERS OF GEOLOGY. Lect. VIII. 



to the equivalent deposits of England. These Devonian 

 beds are covered by carboniferous strata, distinguished, as 

 in Europe, by marine shells of the genera, Leptcena, 

 Bellerophon, Euomphalns, Goniatites, &c, associated with 

 land plants. 



7. Organic Remains of the Devonian. — The deposits 

 comprised under the name of the Old Red were formerly 

 regarded as very sterile in organic remains, and classed 

 among the so-called Transition rocks, in which, it was sup- 

 posed, traces of animal life first appeared. Modern re- 

 searches have, however, shown that though many of the 

 strata are locally unproductive in fossils, yet others abound 

 in the remains of corals, shells, crustaceans, and fishes ; 

 the marine fauna of this epoch being extremely rich, 

 and containing certain peculiar types, but, as a whole, 

 forming a connecting link between the zoology of the Car- 

 boniferous system which followed, and the Silurian which 

 preceded it. 



Ichthyolites are abundant in the sandstones of Caithness, 

 Cromarty, and other Devonian localities in Scotland, but 

 shells are rare; while in Devonshire, testacese and crusta- 

 ceans are numerous. 



Plants. Of the vegetable kingdom, the only traces found 

 in the Devonian system — with the exception of occasional 

 intercalations of thin layers of coal, and carbonaceous strata 

 ■ — are those of fucoid plants, impressions of which appear on 

 the surfaces of many of the laminated sandstones. In the 

 lower Devonian strata in Forfarshire these supposed fucoid 

 remains are very abundant, and are often accompanied with 

 groups of small flattened hexagonal carbonaceous bodies, 

 which occupy slight depressions in the stone or shale ; 

 these fossils, Mr. Lyell believes to be the eggs of gastero- 

 podous mollusca, for they closely resemble those of the 

 recent Naticd* 



* Elements of Geology, p. 151. 



