114 Horner's Geological Address. 



nounce the end of the long palaeozoic period, and the begin- 

 ning of a new order of zoological conditions. 



It is remarkable, however, that palaeozoic vegetable forms 

 reappear, as I shall afterwards more particularly shew, in 

 beds much newer than the Trias ; for, in the Alps, in many 

 parts of a series of beds, which two such experienced geolo- 

 gists as M. Elie de Beaumont and M. Sismonda unhesitat- 

 ingly 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 peculiari- 

 ty, that while the base of the Permian rocks frequently oc- 

 curs 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 unconformable with the up- 

 per members of the Permian system. Too much stress, how- 

 ever. 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 im- 

 mediately 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 

 conformable, and even have a similarity in lithological charac- 

 ter. 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 Rus- 

 sia has not only given us the evidence, at full length, of his 

 opinions, but brings conviction to our minds by a more gra- 

 phic, and more impressive form of testimony than it was pos- 

 sible to produce in his abridged sketches. This system is 

 developed on an enormous scale in European Russia, repos- 



