182 PROCEEDINGS OF THE GEOLOGICAL SOCIETY^ 



constitutes the remnant of the earlier creation of animals, and ex- 

 hibits the last of the partial and successive alterations which those 

 creatures underwent before their final disappearance. The dwindling 

 away and extinction of many of tli^e types, produced and multi- 

 plied in such profusion during the anterior epochs, and the creation 

 of a new class of large animals, the Saurians, clearly announce the 

 end of the long palaeozoic period, and the beginning of a new 

 order of zoological conditions. 



It is remarkable however that palaeozoic vegetable forms reappear, 

 as I shall afterwards more particularly show, in beds much newer 

 than the Trias ; for in the Alps, in many parts of a series of beds 

 which two such experienced geologists as M. Elie de Beaumont and 

 M. Sismonda unhesitatingly declare to belong to the Liassic period, 

 plants have been found which so skilful a fossil botanist as M. Adolphe 

 Brongniart has not been able to distinguish from species found in 

 the Carboniferous series. There is besides this peculiarity, that while 

 the base of the Permian rocks frequently occurs in unconformable 

 stratification with the Carboniferous, there is no example, it is said, 

 in any part of Europe, of the Trias being found in stratification un- 

 conformable with the upper members of the Permian system. Too 

 much stress however, Sir R. Murchison observes, ought not to be laid 

 on this last circumstance, as evidence of a gradual passage in time 

 from the Permian to the Triassic series, because sedimentary matter 

 may be thrown down on the edges of older strata immediately after 

 their dislocation, and that dislocation may have taken place without 

 any great period having elapsed since the strata were deposited. On 

 the other hand, if the sea-bottom were undisturbed, there might have 

 been, so far as mineral structure is concerned, an immense interval 

 of time between the deposition of two beds that are perfectly con- 

 formable, and even have a similarity in lithological character. And 

 such in fact is the case. " Throughout whole regions of Russia the 

 older deposits are clearly separable from each other by means of 

 their respective fossils, although they are all apparently conformable." 

 The different memoirs which Sir R. Murchison had read before 

 this Society made us acquainted with the leading features of the 

 Permian system ; but his great work on Russia has not only given 

 us the evidence, at full length, of his opinions, but brings conviction 

 to our minds by a more graphic and more impressive form of testi- 

 mony than it was possible to produce in his abridged sketches. This 

 system is developed on an enormous scale in European Russia, repo- 

 sing upon carboniferous strata, throughout more than two-thirds of a 

 basin which has a circumference of not less than 4-000 English miles ; 

 that is, it occupies a space greater than twice the area of France. 



The palaeozoic series in North America ends with the carboni- 

 ferous rocks ; for although that and the inferior groups are deve- 

 loped on so great a scale, a narrow zone of red sandstone on the 

 Atlantic slope, celebrated for containing the footmarks of giant 

 birds, which in the opinion of Professor Rogers belongs to the Trias, 

 is almost the only sedimentary deposit between the Carboniferous and 

 the Cretaceous rocks. 



