300 R. Etherklge, jun. — New Carboniferous Mollusca. 



But making every allowance for our ignorance of past life-periods, 

 and also for the imperfection of tlie geological record, I think it can 

 be clearly demonstrated that there is " a eontinuity of life on the 

 earth " from the earliest dawn of that life to our own day : that the 

 changes which have taken place have resulted from alterations in 

 physical conditions, such as the elevation and subsidence of the land, 

 bringing about changes of climate, causing migrations and modifi- 

 cations in distribution, in numbers, size, etc. That from period to 

 period, in the far-off past, the various groups have in turn prevailed 

 as leaders in the kingdom of animal and vegetable life. Thus 

 in early times the Cephalopoda ruled, later on the Crustacea 

 came to the fore, then probably Fishes took the lead, but were 

 speedily overpowered by the Saurians. These Land and Sea 

 Eeptiles then prevailed until Mammalia appeared upon the scene, 

 since when it doubtless became a struggle for supremacy until Man 

 was created. Then came the age of Invention ; at first of flint and 

 bone implements, of bows and arrows and fish-books ; then of spears 

 and shields, swords and guns, lucifer-matches, railways, electric 

 telegraphs ; since when even the great whale has given in his ad- 

 hesion to the new King Steam, and is dying out of the way quietly. 



One fact more deserves to be borne in mind: that is, the immensity 

 of time since life first began. Originally only Plutonic or Metamor- 

 phic rocks existed. As these yielded to weathering, they produced 

 sediments which assisted to form the PahTeozoic rocks. Again, these 

 in their turn were denuded wherever elevated above the sea, and 

 assisted to form by their wreck the Mesozoic strata, from all of 

 which the Tertiary have in like manner been made. But animals, 

 by their labours and accumulated skeletons, have probably con- 

 tributed more largely than any other source to build up the masses 

 of the sedimentary rocks. Nor is it to the highest in the zoological 

 scale that this task of mountain-building has been entrusted by 

 Nature ; on the contrary, the two humblest classes, the Protozoa 

 and CcELENTBRATA, have been chosen: to rear these imperishable 

 monuments ; whilst our great stores of mineral fuel, upon the 

 continuity of which the vast industries of this country depend, are the 

 result of the accumulated growth and decay of lowly organized 

 Cryptogamic plants, allied to ou.r existing Club-mosses and 

 EquisetaccEe. 



II. — Notes on Carboniferous Lamellibranchiata (Monomyaria). 

 By Robert Ethekidge, Junior, F.G.S. 

 Genus Pecten, Bruguiere. 

 (PLATE XIII.) 

 Pecten Sowerbii, McCoy. Plate XIII. Figs 1 and 2. 

 P. Sowerbii, McCoy. Synop. Garb. Fos. 1844, p. 100, pi. 14, fig. 1. 

 F. Valdaicus, Keyserling and De Verneuil. Murchison's Geol. Russia, 1845, vol. ii. 

 p. 328, pi. 27, fig. 9. 

 „ „ D'Orbigny. Prodrome de Pal. 1849, i.. p. 138. 

 P. Bathus, D'Orbigny. Prodrome de Pal. 1849, i. p. 139. 

 P. Sotvtrbii, Morris. Cat. Brit. Fos, 1854, p. 175. 

 Amusiuni Sowerbii, McCoy. Brit. Pal. Fos. 1855, p. 478. 



