(37) 



Floor- and wall-cases No. 4 are devoted to specimens of 

 Carboniferous plants in the genera Lepidodendron, Sigillaria 

 and Stigmaria, in order to show the variation in the arrange- 

 ment and shape of the leaf scars and the difference between 

 specimens with the bark preserved and those which have been 

 decorticated. 



Floor-case No. 5 contains types of early Mesozoic time : 

 Triassic and Jurassic Periods. — The plant remains in this 

 case are mostly sago-palms or cycads, with a few cone-bearers 

 and fern-plants, besides specimens of the so-called " Glossop- 

 teris flora," a flora of uncertain botanical relationship, which 

 flourished in the transition period between Paleozoic and 

 Mesozoic time, particularly in the southern hemisphere, and 

 may yet be represented by the living South African genus 

 Stangeria, a cycad having leaves with pinnately arranged 

 forking veins, similar to ferns. 



Floor-case No. 6 embraces plant remains from the rocks 

 of later Mesozoic time: Lower and Middle Cretaceous Pe- 

 riod. — These specimens represent the first appearance of the 

 higher seed-bearing plants (Angiosperms) , the type which is 

 dominant in the existing flora. The genera are in most in- 

 stances apparently identical with those now in existence, but 

 the species are extinct. The plants of the Lower Cretaceous 

 consist largely of ferns and cone-bearers, while those of the 

 Middle Cretaceous show a preponderance of angiosperms. 



Floor-case No. 7 is arranged to show specimens of the 

 Middle Cretaceous flora found within the limits of the City 

 of New York, on Staten Island, or in the immediate vicinity, 

 in New Jersey and on Long Island. 



Floor-case No. 8 contains specimens from the Middle Cre- 

 taceous of the western States. Those from the Dakota 

 Group are exceptionally fine, many of them being perfectly 

 preserved and showing both cast and impression of the same 

 leaf as counterparts. 



Floor-case No. 9 is devoted to plants of the Upper Cre- 

 taceous (Laramie Group), and completes the vegetation of 

 Mesozoic time. 



