CYCADACE.E. 15 



cycadean leaf. Another possible Tertiary cycad is described by 

 Ettingshausen from the Miocene beds of Leoben ; to this the 

 name Ceratozamia Hoffmanni, Ett., has been, assigned. 1 The single 

 imperfect pinna which is figured by the author of the species, 

 does not afford sufficient evidence that it belongs to this particular 

 recent genus. Granting its cycadean nature, and even this entails 

 a considerable amount of faith, there is surely no reason why the 

 fragment should not be referred to some other genus than the one 

 chosen; one might suggest "cycadean pinna?" as a more fitting 

 term than C. Hoffmanni, Goppert's Tertiary species of a 

 Greenland cycad, Zamites arcticits* is founded on a fairly good 

 specimen, and certainly appears to be correctly included among 

 the Cycadacea. These few examples of fragments described by 

 various writers as cycadean fronds, sufficiently demonstrate the 

 meagre relics of this order of gymnosperms in Tertiary rocks. 



In his Monograph on the Jurassic cycads, Saporta 3 has given 

 a useful and critical summary of the history of the literature on 

 fossil Cycadaceae, to which is added a series of definitions of the 

 chief characters by which the several genera of fronds may be 

 recognized. Certain suggested emendations of some of these 

 diagnoses will be found under the head of the respective genera 

 in the descriptive part of this Catalogue. 



Without following the gradual additions to our knowledge of 

 fossil cycadean fronds during the last sixty or seventy years, 

 or attempting to discuss the numerous classifications proposed by 

 various writers, it may serve a useful purpose to draw attention 

 to some of the difficulties and possible sources of error associated 

 with the investigation of the past history of cycads. 



The characters generally made use of in the separation of 

 distinct genera of fossil cycadean leaves may be enumerated as 

 follows : (i.) The method of attachment of the pinna? to the 

 rachis, and whether persistent or deciduous, (ii.) The nature of 

 the base of the pinna?, auriculate or gradually tapered, etc., the 

 presence or absence of a distinct basal callosity, (iii.) The pinna 

 apex, whether truncate, acuminate, etc. (iv.) Venation, (v.) The 

 angle of insertion of the pinnae on the rachis ; the alternate 



1 (3), p. 272, pi. iii. fig. 10. 



2 Goppert (2), p. 134, pi. ii. figs: 9 and 10. 



3 (A. 2), Pal. Fran9. [2] vol. ii. 1875, pp. 26-45. 



