xii PROOFS, ILLUSTRATIONS, AUTHORITIES, ETC. 



animals which they embrace. The most fortunate approximations 

 which naturalists have attempted at different epochs, have received 

 striking confirmation by modern palaBontological discoveries, and 

 that often when those to whom we owe them were unconscious of it.^ 

 These results are so striking, that even now, in some classes of 

 animals, the knowledge of fossils, and their order of succession, may 

 serve as a guide to correct the zoological system, just as, on the 

 other hand, the advanced state of our anatomical knowledge will 

 lead us to a correct determination of the geological age of certain 

 deposits, even although we should not discover in them any fossil 

 species identical with those of well determined formations of the 

 same era." Agassiz : Monographic d-es Poissons Fossiles. ^ 



" 1 venture to say that the time will come when the relative a^e 

 of fossils, within certain limits, will be as satisfactory a guide in 

 assigning them their normal position in a natural system, as the 

 facts derived from the study of their structure so intimate are the 

 connections existing between all parts of the wonderful plan dis- 

 played in creation."' Agassiz: Proc. of Am. Assoc.for Adv. oj 

 Science at Charleston, 1850. Jamesons Jour., April, 1851. 



Polypiaria. "Amongst the most simply organized of the Silu- 

 rian species, and amongst those found in the beds of oldest date, are 

 the fossils called graptolltes., which seem to have been the horny 

 skeletons of animals not unlike those which are often met with on 



the coral and sea-weeds of our own coast Polyps, as animals 



of this humble class' are called, appear to have been among the first 

 of created beings, and are also those which have been changed least 

 since the period of their original introduction up to the present time. 

 Their .extreme simplicity of structure would enable them to live 

 through many changes, since they could adapt themselves to altered 

 conditions of temperature and position, at times when almost every 

 other animal was destroyed ; and accordingly, in the species of them 

 found fossil, there is far less difference from existing nature than is 

 the case with any other creatures. These little corallines, and th 

 larger and more important group of true corals, as they commenced 

 existence so early, seem' also to have been comprised within a very 

 limited number of natural families, and some particular species pro- 

 bably extend completely through the whole number of beds of the 

 first' great epoch." Ansted: ^Pic. Sketches of Creation. 



Foraminifera." A group of minute shelled animals belonging 

 to the sub-kingdom Acrita; marine, inhabiting sea-weeds and the sea- 

 bottom ; generally free, but sometimes attached to shells, corals, &c.^ 

 Animal gelatinous, occupying a calcareous shell, which is formed of 

 a succession of cells or chambers, arranged in a straight, spiral, or 

 agglomerated manner. The cells communicate one with another by 

 one or more apertures, or by a narrow neck or tube, through which 

 the animal matter is continued from cell to cell," ^etc. ' Each new 

 articulation produced by gemmiparous generation." 



Only twelve species are described as belonging to formations before 



