Devonian Bocks, 89 



common to the Silurian beds of Europe and America, whe- 

 ther of the upper or lower division, he can confidently affirm, 

 that it is not greater than a naturalist would have antici- 

 pated, from the analogy of the laws governing the distribu- 

 tion of living invertebrate animals. 



While the remains of fucoid plants are met with abun- 

 dantly in the Silurian rocks of Europe, and in the lowest 

 members of the series, I am not aware that any vestiges of 

 land plants have yet been discovered in them^ Sir R. Mur- 

 chison says, that, in the older palaeozoic rocks of Russia, he 

 met with no signs of terrestrial fossil vegetables. Fucoids are 

 plentifully distributed through every part of the series in 

 North America ; and Mr Lyell also states, that, in the Hamil- 

 ton group, which corresponds in many of its fossils with the 

 Ludlow rocks, and which, singularly enough, is met with in 

 the neighbourhood of Ludlowville, remains of plants allied to 

 Lepidodendron have been found associated with fossils agree- 

 ing perfectly with European Upper Silurian types ; and that 

 other plants allied to these, and ferns, have been met with 

 in the lowest Devonian strata of New York, associated with 

 fossil shells closely allied to the Silurian. Thus we have 

 additional proof, if any were wanting, of the existence of dry 

 land at the time of the deposition of these Silurian beds. 



Devonian Rocks. 

 The Silurian rocks of Russia in Europe are covered con- 

 formably by deposits, the identity of which, with the Devon- 

 ian, or old red sandstone, series of the British Isles, Sir R. 

 Murchison and his companions clearly made out. They 

 extend over an area of not less than 150,000 square miles, a 

 superficies greater, by nearly one-third, than that of Great 

 Britain and Ireland together. This monotony of feature over 

 so vast a space is even greatly surpassed by the Permian 

 rocks ; and when it is considered that this uniformity is com- 

 bined with a stratification rarely deviating from the horizon- 

 tal, never thrown up into natural sections, and that the in- 

 vestigation of them can only be carried on where the beds 

 are exposed in the banks of rivers, geologists can appreciate 

 the tedium and labour of exploring such a country, and can- 



