PALEOZOIC TIME — DEVONIAN. 



595 



dolomytes are referred to the Middle Devonian, the Stringocephalus zone of Europe, con- 

 taining characteristic specimens of 8. Burtini, one specimen measuring 7 by 5 inches in 

 diameter. 



LIFE. 



Plants. — In the beds of the Hamilton period, the evidences of verdure 

 over the land are abundant. The remains show that there were trees, as 

 well as smaller plants ; that there were forests of moderate growth, and 

 great jungles over wide-spread marshes. The plants included Lycopods, Ferns, 

 and Equiseta, the three orders of Acrogens, or higher Crytogams ; and also 

 Gymnosperms, among Phaenogams. 



1. Lycopods. — The Lycopods generally have scars over the exterior, 

 much like those of a branch of spruce after the leaves have been removed. 

 A Hamilton specimen of the Lepidodendron primcevum is represented in 

 Fig. 894, and of another species in Fig. 895. L. Gaspianum (see Fig. 855) 

 has been found in the Genesee slate of 'New York and Pennsylvania. 



2. Ferns. — Many species of ferns have been described from beds of the 

 Hamilton period, the most of them from those of St. John, New Brunswick. 

 One species, a Neuropteris, is represented in Fig. 897; part of a frond of 

 another, an Archceopteris, in Fig. 898, and a single leaflet, illustrating the 

 divergent nervures of this genus, in Fig. 899. Large trunks of tree-ferns 

 have been found in the Hamilton beds of New York and Ohio, showing that 



894-899. 



894. 



896. 



897. 



V:L'i :AMM 



AcEOGEjfS. — Fig. 894, Lepidodendron primEevum ; 895, Sigillaria Halli ; 896, Cordaites Kobbii ; 897, Neuropteris 

 polymorpha; 898, 899, Archaeopteris Jacksoni. Fig. 894, Lesquereux ; 895, Meek; 896-899, Dawson. 



there was beauty of foliage in the forests, if not of flowers. One of them, 

 Psaronius Erianus Dawson (1870, 1871) had a trunk three to four feet in 

 diameter, and was therefore a tree of large size. 



