58 AN INTRODUCTION TO THE STUDY OF FOSSILS 



bined characters of ferns and cycads. Recently true seeds have 

 been found attached to stalks bearmg the fern-like leaflets. 

 These plants were accordingly shown to be primitive seed-plants 

 intermediate between the ferns and the cycads, a relationship 

 indicated by the name applied to them. In some the cycad 

 features predominate, in others those of the ferns. 



Of those fruits which may belong to this gymnospermous 

 line, one of the most important yet discovered is that show^n 

 in the adjoining figure iS a. It accompanies cycadofilicalean 

 foliage in some abundance in the ironstone nodules of Mazon 



Fig. iSb. — Examples of the cycadofilicales (an extinct class combining characters 

 which to-day are separated into the distinct groups of ferns and cycads). A, 

 Neuropteris hirsuta Lesquereux ; a portion of two leaflets (pinnules, p.), with the 

 small stipules {s.) at their base. B, an almost complete frond of N . smithsii Lx. 

 Both (natural size) from the Pennsylvanian period of Pennsylvania. (From 

 Lesquereux.) 



Creek, Illinois, and in its outer features closely resembles the 

 fruits described in England as the seeds of Neuropteris. The 

 full meaning of this ancient type of fructification is not yet 



