( I22 ) 



may be caused by worm burrows; Phytopsis, which may 

 be a coral; Plumulina, which may be a hydroid; Dendro- 

 phycus, which may be current-markings; and Dictyolites, 

 which are most likely sun-cracks. All of these, however, 

 have at one time or another been definitely regarded as 

 the remains of marine plants and were originally so de- 

 scribed and classified. 



In these cases and in wall-case No. 2 are also the remains 

 of the earliest fern-plants and their allies (Pteridophyta) 

 of Devonian and Carboniferous age, represented by 

 Lepidodendron, Sigillaria, and Catamites, and the early 

 seed-bearing plants, the cone-bearers (Gymnosperms), 

 represented by Cordaites, with the fossils under Trigono- 

 carpon, Rhabdocarpon, and other genera. 



Floor-cases Nos. 2 and 3 and wall-case No. 3 contain 

 specimens of Carboniferous age, for the most part ferns or 

 fern-like plants, which were originally described as ferns, 

 but which are now placed in a different group, the Cycado- 

 filicales, that is, plants that had characteristics of both 

 the ferns and the sago-palms, but more closely related to 

 the latter than to the ferns. 



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

 Carboniferous plants in the genera Lepidodendron, Sigil- 

 laria, and Stigmaria, in order to show the variation in the 

 arrangement 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 

 "Glossopteris flora," a flora of uncertain botanical relation- 

 ship, 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. 



