Palaeozoic Geology. 561 



dantly found in both hemispheres. As soon, however, as we have 

 advanced through this zone, a new era is announced by the pre- 

 sence of the earliest Vertebrata. Tlie minute and curious fishes in 

 the uppermost bed of the Ludlow rock, are the earliest precursors 

 of many singular ichthyolites which succeed in that enormous for- 

 mation, termed from its mineral character in Scotland and parts of 

 England, the Old Red Sandstone. But in this as in nearly every 

 other deposit, lithological characters are fugitive, and the red, green 

 and yellow sands of the North, are found even in our islands, as 

 in Devonshire and the adjacent tracts, to be replaced by black 

 schists and limestones. But here again zoology enables us to in- 

 terpret the language of nature, for it was merely by seeing the 

 letters of the alphabet spread out before him in a cabinet, and 

 without even having visited the country, that Mr. Lonsdale was 

 led to conceive that a large portion of this tract, though very 

 dissimilar in mineral aspect, would prove to be of the same age as 

 the Old Red Sandstone. I need not tell you how the researches of 

 Professor Sedgwick and myself, which first indicated the presence 

 of some members of the carboniferous system of that tract, after- 

 wards confirmed these views, nor need I remind you that we have 

 since extended them to various parts of Germany and Belgium, 

 for the abstracts are already in your Proceedings and the memoir 

 is about to appear in your Transactions. 



I must here, however, acquaint you, that the paper by ourselves 

 upon the Rhenish provinces is admirably illustrated by a description 

 of the Devonian fossils of that region, prepared at our request by 

 M. E. de Verneuil and M. d'Archiac, in which many new genera 

 and species are established, and the group is delineated with close- 

 ness of research and profound knowledge of natural history. In the 

 same communication these authors offer a general table of Palaeo- 

 zoic fossils, which in sustaining in the strongest manner the true 

 intermediate character of the Devonian system, as suggested by 

 Mr. Lonsdale, seems to be one of the most valuable documents yet 

 presented to our consideration, in leading us to view the palaeozoic 

 rocks as a great tripartite series comjjosed of the Carboniferous, De- 

 vonian, and Silurian systems. 



Further, I would specially draw your attention to the enlarged 

 views of our French coadjutors, derived from extensive study, in which 

 they estimate the relative increase and decrease of various genera 

 and species of fossils in the three divisions of tlie earlier periods, 

 and show that whilst a few species (twenty only in upwards of 2750 

 distinct species or well-marked varieties) range throughout the tri- 

 partite series, yet that each system has a distinctly typical fauna, wlie- 

 tiicr we derive our conclusions from researches in our own parts of 

 Europe, or from an examination of American and Russian forms*. 

 Whilst speaking, however, of this table, I nmst at the same time 



• M. de Verneuil has, with ray full consent, enriched this general table 

 of comparison by the addition of the names of all the new species ahd 

 characteristic palscozoic types collected in our two visits to Russia, and 

 the description of which wc are now preparing. — March 1842. 



