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GEOLOGY. 



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

 zoophyta, but concliifera ; 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," Sir E, 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 group, Nereites Sedgwicldi. 



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 Avater 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 should be remarked, that these beds in which the traces of life are 

 occasionally detected, the oldest of the fossiliferous rocks, are by some geologists regarded 

 as forming a distinct and independent system, while others associate them with the 

 ensuing Silurians, as the basis or bottom-rocks of that series. 



