226 THE RARITAX FLORA. 



were collected. He seems disposed to attach considerable weight 

 to their resemblance to a helianthoid flower, and points out that 

 they differ from the typical Williamsonias in the apparent ab- 

 sence of the internal seed-bearing cone. The nature of the re- 

 mains does not enable one to form a positive opinion, neverthe- 

 less their resemblance to well-preserved Williamsonias which are 

 undoubtedly cycadean, lends more support to a theory of rela- 

 tionship with the latter group of plants than with the essentially 

 modern Compositse. The increased interest in the Cycadales 

 called forth in recent years, has served to establish the cycadean 

 affinity of a number of species of Williamsonia, and structural 

 material has in a measure cleared up their morphology, so that 

 while this order of plants had commenced its final decline in Rar- 

 itan time, it must be remembered that it was exceedingly abun- 

 dant in the older Cretaceous deposits of Maryland and Virginia, 

 and remnants of cycad fronds are by no means uncommon in the 

 Raritan deposits. 



Many supposed Williamsonias have been described, most of 

 those from American rocks being founded upon exceedingly im- 

 perfect material. Perhaps the form most like the present species 

 is Willianisonia delazcarensis Berry^ described from the Mag'othy 

 formation of Delaware. It may be questioned if the forms from 

 Marthas Vineyard which Hollick (loc. cit.) refers to WiUiani- 

 sonia problcmatica are not more properly referable to JJllliani- 

 sonia delazvarensis. This is especially true of this author's figures 

 29 to 32, while figures 27 and 28 may be lateral views of the 

 compressed transverse views of the objects described as IVil- 

 liamsonia Riesii. From nearlv hontotaxial horizons JVil- 

 Uamsonia elocata has been described by Lesquereux- from the 

 Dakota sandstone, and I'Villiamsonia cretacea has been described 

 from: the Atane beds of Greenland by Heer^. The Williamsonias 

 described by Ward from the older Cretaceous are all extremely 

 poor and of doubtful affinities, but Williamsonia virginiensis de- 

 scribed by Fontaine from the older Potomac of Virginia, is 



'Johns Hopkins Univ. Circulars, No. 199, 1907, p. 84, f. 4. 



* Lesq.. FI. Dakota Group, 87, pi. 2. f. g, ga, 1892. 



'Heer, Fl. Foss. Arct., vol. VI, Abth. 2: 59, />/. 12, f. i; pi 13, f. 9, 1S82. 



