750 



HISTORICAL GEOLOGYo 



LIFE. 



1. Triassic of the Atlantic Border. 



Plants. — The vegetation of the Triassic was characterized not by 

 Sigillarids and Lepidodendrids, like that of the Carbonic era, but by Cycads, 

 Conifers, Ferns, and Eqniseta. 



As the Cycads were a prominent feature of the forests in both the Triassic 

 and Jurassic periods, a figure of a common East India species, Cycas circmcdis 

 ( ^ yio ) ^^ given on page 434. Its rehxtion to Conifers, both groups being 

 Gymnosperms, notwithstanding its palm-like foliage, has already been 

 explained. Portions of leaves of two species related somewhat to the 

 modern Zamia are represented in Pigs. 1156 and 1157. 



Conifers existed of the genera Voltzia (differing little from Walcliia of 

 the Permian, page 705), Baiera, and Araucarites. Stems, leaves, cones, and 

 trunks of such trees are not uncommon. Perns were numerous, of the genera 

 Pecopteris (Pig. 1159), Tceniopteris (Pig. 1160), Clathropteris (Pig. 1158), 

 and others related. Some of the Equiseta (Calamites) had a breadth of 

 stem of four inches or more. 



Animals. — The Triassic beds of the Atlantic border have afforded no 



marine species of any kind; all are 

 either of fresh or brackish waters, or 

 else terrestrial. 



1161 



1161-1163. 



1162 



Figs. 1161-1163, Estheria ovata. Fig. 1161 

 1162, E.Emmons; 1168, L. Sanford. 



Lyell; 



1. Crustaceans and Insects. — The 



Crustaceans observed are mostly 



Ostracoids. The little shells (Pigs. 



1161-1163) are abundant in some 



beds of shale. 



The presence of Insects is known from their tracks and from the discovery 

 of the larves of one species. These larves (Pig. 1164) were found by E. 

 Hitchcock rather abundantly in shales at Turner's Palls, and have since 



1164-1169. 



1164 



1166 



1167 



> \> 



} 



116S\ V 



/ 





w 

 w 



\ ^ 



Vi 



\l 





\l 



\l 



V ^ 



\\ 



\'j 



V ^ 



\ 



1169 



\ 

 \ 



Iksects. — Fig. 1164, Insect larve, Mormolucoides articulatns ; 1165-1167, tracks of Insects; 1168,1169, tracks 

 of Crustaceans (?). Fig. 1164, from Scudder ; 1165-1169, E. Hitchcock. 



been obtained at Montague, and at Horse Race in Gill, Mass. The Insect 

 was a iSTeuropter. Pi.gs. 1165 to 1167 are of tracks from the Connecticut 



