ANNIVEBSARY ADDRESS OF THE PRESIDENT; xliii 



§ Palceontohgh-al Periods. 



"When tracts of the old sea-bed so far apart as Wales from Lisbon, 

 Bohemia, Sweden, or New York, the Arctic zone, the Himalaya 

 range, or China are compared, and in all these countries the Lowest 

 strata are found to be filled with many forms of life remarkably 

 similar*, not only in the mass of the rocks, but also often in tbe 

 il groups of strata one above another, taken in the same order, 

 geologists conclude that these strata, which, taken separately or taken 

 in mass, have such remarkable agreement, were produced in the 

 same period of the earth's history. Tin- agreement of the fossils 

 being for the most part due to the deposition of the strata in one 

 on ;i 1 1 i i - basin, or to the free communication between one such basin 

 and another, so that the species of marina animals might be dif- 

 fused over parts of caih. we have no reason to doubt that similar 

 Successions of deposits — lying in the same part of a similar general 

 series of strata, and containing similar kinds of fossds grouped in a 

 similar manner — were of approximately contemporaneous origin. 

 In several of these cases they have a similar base of metamorphic 

 rocks, and a similar cover of Devonian or Carboniferous, rocks, — all 

 circumstances giving independent testimony to the truth of our 

 genera) conclusion. We might further confirm it by the evidence 

 of displacements <'f the strata, at definite epochs and through defi- 

 nite {groups of the strata — movements which have raised tin- Silurians 

 before the date of the coal, and remodelled the whole area of the 

 land and Beg before the Trias and after the Chalk. 



It has. indeed, been objected that this conclusion is illogical — that 

 id* nt it y of time cannot he inferred from similarity of conditions — 

 that the successive conditions of Silurianism. Devonianism, &C., may 

 lie due to a necessary sequence i" the order of natural phenomena, 

 and may ha\e commenced <il qny tiuu, round any land which, by 



rising from the deeps of the ocean, came within the zone of light 



and life in the waters. The objection i s »"• valid. The dates or 



the uprising of land are, indeed, as here suggested, various; but 

 according to the period when each came under the influence of the 

 conditions requisite for life are the deposits and the fossils which 

 surround it. An elevation which can he proved to have happened 



after the ( 'oal is followed by shore- and sea-deposits having the fossils 



of the period, imt the primeval fossils; the land which is raised 



tie- vegetation of the period, not the primeval vegetation* 



Thus the series of strata and of fossils, taken as a wlnde, i> but Onfl 

 function of the elapsed time ; hut the terms of the series appa- 



tliciv is a stronge misplacement at the foot of tbe page, of the words "and of ma: 



:• month marine origin." The] should lime Been on page 90, so '•- to fan- 



iluili- the beds which Ballon on thai page m marina. She Mnaa is totailj eon- 



lus,ii i,\ iiii. mishap. 



* // i the Limestone of North Somerset m well m in ilu» 



lime-! D i "ii ; mill th. '■ Lamestone of Bfon Fork 



tvbicli was found bj < '-i|»i. Maclure st I'nu.-. - - aU. . j M ih<- 



Limest laid ami Devonshire, and m thi x roup of the Aiow 



World. 



d2 



