EGETABLE KEMAINS. 57 



afforded by the extinct family of Trilobites, (see Plates 45 

 and 46) to the history of which we shall devote pecuUar 

 consideration under the head of Organic Remains, Al- 

 though nearly fifty species of these Trilobites occur in strata 

 of the transition period, they appear to have become extinct 

 before the commencement of the secondary series. 



The Radiated Animals are among the most frequent or- 

 ganic remains in the transition strata ; they present nume- 

 rous forms of great beauty, from which I shall select the 

 family of Crinoidea, or hly-shaped animals allied to Star-fish, 

 for peculiar consideration in a future chapter. (See PI. 47, 

 Figs. 5, 6, 7.) Fossil corallines also abound among the 

 radiata of this period, and show that this family had entered 

 thus early upon the important geological functions of add- 

 ing their calcarious habitations to the solid materials of the 

 strata of the globe. Their history will also be considered 

 in another chapter. 



Remains of Vegetables in the Transition Series. 



Some idea may be formed of the vegetation which pre- 

 vailed during the deposition of the upper strata of" the tran- 

 sition series, from the figures represented in our first plate 

 (Fig. 1 to 13.) In the interior regions of this series, plants 

 are few in number, and principally marine;* but in its 

 superior regions, the remains of land plants are accumu-' 

 lated in prodigious quantities, and preserved in a state 

 which gives them a high and two-fold importance ; first, as 

 illustrating the history of the earliest vegetation that appear- 

 ed upon our planet, and the state of cHmate and geological 

 changes which then prevailed :f secondly, as aflecting, in 

 no small degree, the actual condition of the human race. 



* I\I. A. Brongniart mentions l!ic occurrence of four species of fucoids in 

 the transition strata of Sweden and Quebec; and Dr. Harlan has described 

 another species found in the Alleghany Mountain?. 



■j- The nature of these vegetables, and ib.cir relations to existing species, 

 will be considered in a future chapter. 



