194 GEOIvOGICAIv SURVEY OF NEW JERSEY. 



therefore to understand how any particular living flora has 

 reached its present condition it is necessary to know something 

 about the changes, in their proper sequence, which the region 

 has undergone in the past. 



Within the boundaries of the state are geologic formations 

 representing all the great time divisions, Eozoic, Palaeozoic, 

 Mesozoic and Neozoic, and rocks of all the included geologic 

 periods, with the exception of Carboniferous and Jurassic, but 

 for the purposes of this report the vegetation of Palsezoic time 

 may be disregarded. 



MESOZOIC TIME. 



Triassic Period. During this period the shore line of the 

 North American continent, so far as New Jersey is concerned, 

 extended irregularly from about the vicinity of Mahwah to a few 

 miles south of Phillipsburg. Everything indicates that for a 

 long time the Atlantic border had been slowly sinking and that 

 the Triassic deposits were laid down in estuaries and lagoons- 

 which were alternately covered by the tides and exposed to the 

 air. The rocks are largely conglomerate, sandstone or shales, 

 evidently shore or shallow-water deposits, often ripple-marked 

 or -sun-cracked and bearing the footprints of ' reptiles or 

 amphibians. 



The vegetation of the period is but sparsely represented in 

 the collections which have been made in N^w Jersey, but by 

 comparing these with similar collections from other places it 

 may be seen that the vegetation is fairh' representative of the 

 period. Dr. J, S. Newberry has described nine species from the 

 state,* of which three are regarded as pteridophjtes, and the 

 remainder are apparently all referable to the gymnosperms. 

 One living genus {Equisetuni) is recognized in the former sub^ 

 kingdom. 



Thus far, in any collection of Triassic plants which has been 

 made, nothing higher in biologic development than the monoco- 

 tyledons is even indicated, and we may regard the Triassic flora 

 as one composed almost wholly of ferns and their allies, cjcads 

 and conifers, with cycads as the dominant type. 



• " Fossil Fishes and Fossil Plants of the Triassic Rocks of New Jersey and Ihe Connecticut 

 Valley." Monographs of the U. S. Geol. Survey, Vol. XIV. 



