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GEOLOGY. 



most ancient forms of life known to us, should be, not plants, but animals ; not merely 

 zoophyta, but conchifera ; not the lowest grades of their respective classes, but perfectly 

 developed lamelliferous zoophyta, and brachiopodous mollusca." These mollusca, now 

 extinct, lived in the ocean attached to other bodies. They prevail through the older 

 fossiliferous rocks, in connection with a large increase of species, gradually disappear from 

 the sphere of existence in newer formations, and finally vanish in the lias, where only 



one species occurs. In addition to these fossil examples of 

 ancient organisms, traces of Annelidans, the first class in 

 Cuvier's arrangement of articulated animals, have been re- 

 cognised. These are worms with red blood, formed of rings, 

 or annular segments, like the leech and common earth- 

 worm, some of which are naked, while others have a shelly 

 covering, or are protected by a kind of coat formed of 

 agglutinated sand. Their remains are abundant in more 

 recent deposits, but in several instances, upon the older 

 rocks, their traces only are discernible. " Singular con- 

 voluted impressions," Mr. Murchison remarks, " had been 

 observed by the Rev. A. Oliphant, of Llampeter College, on 

 the surface of the building-stone of that place ; and upon 

 submitting some specimens to the examination of Mr. W. 

 Macleay, that profound naturalist pronounced them to have 

 been formed by sea-worms." The engraving represents the instance in question, Nereites 

 Cambrensis, from Llampeter in North Wales, from which the body appears to have been 

 composed of about one hundred and twenty segments. A greater number of segments 

 appears to have distinguished a more slender species, named after the founder of the 

 Cambrian system, Nereites Sedgwickii. 



Such were the creatures that appear to have first crawled upon the stage of life, opening 

 that drama of being in which we are now actors, and in which man, as poet, warrior, and 

 sage, has for some thousands of years played a conspicuous part. Wandering upon our 

 sandy shores, we often in listlessness or idle curiosity overturn the stones in our pathway, 

 and observe existing Nereidina slender worms wriggling in the water and mud and 

 these insignificant animals are the analogues of those forms in which we have reason to 

 believe sensitive life first appeared in our world. " From this origin of organic life, 

 there is no break in the chain of organic development, till we reach the existing order of 

 things ; no one Geological period, long or short no one series of stratified rocks is every 

 where devoid of traces of life. The world once inhabited has apparently never, for any 

 ascertainable period, been totally despoiled of its living wonders. But these have many 

 changes in the individual forms ; great alterations in the generic assemblages ; entire 

 revolutions in the relative number and development of the several classes. Thus the 

 systems of life have been varied from time to time, to suit the altered condition of the 

 planet, but never extinguished. The earth, once freed from its early inadequacy to 

 support life, according to the appointed laws, has since been prolific of vegetable and 

 animal existence." It will be observed, that, contrary to what we might have naturally 

 anticipated, animals seem to have preceded plants in the occupation of the globe, for no 

 vegetable remains have been discovered in the older fossiliferous rocks. But we are not 

 positively certain that this was the case, for though the mollusca in the Cambrian strata 

 might prey upon each other, there is some antecedent probability in favour of marine 

 plants co-existing with marine shell-fish ; and it is perfectly possible to conceive, that in 

 the metamorphic change which the slate rocks have undergone from the protrusion of 

 igneous masses, all remains and traces of vegetable fibre have been obliterated. 



