144 



is impossible to retain the specific names TJmites expansus, T. divari- 

 eatus, T. articulatus, and T. cupressiformis as designations of distinct 

 species ; it is by no means unlikely that among the num.erous- 

 specimens -we have more than one species represented, but I am 

 unable, with the available data, to recognise any characters on 

 ■which it is possible to found distinctive diagnoses. I have therefore 

 adopted the plan of using Sternberg's name Thuites expansus as- 

 a comprehensive designation for the coniferous twigs from Stones- 

 field which agree more or less closely with the example represented 

 in PI. IX. Fig. 1. It has been pointed out by some previous 

 writers that too many specific titles have been employed. Saporta,' 

 for example, includes under Palaocyparis expansa the species 

 T. expansus, T. articulatus, and T. dkaricatus. Some of the 

 drawings published by Saporta were made from specimens in. 

 the Oxford Museum, and Sternberg's figures are also taken from 

 the same source. While most authors adopt the generic name 

 Thuites, which implies a decussate arrangement of the scale-leaves, 

 as in recent Cupressinefe, a few have substituted other designations. 

 Schimper^ notices that the leaves of Thuites expansus are not 

 always in opposite pairs, and substitutes the generic name 

 Eehinostrobus. 



Specimens of Thuites expansus are abundantly represented in 

 several museums ; in the Manchester Collection there is a very well 

 preserved branch (No. 265) in which the whorled arrangement of 

 the broadly triangular leaves is clearly shown. One of the best 

 specimens of a female cone is in the Sedgwick Museum, Cambridge, 

 but none of the examples are suflSiciently well preserved. to enable 

 one to determine the structure of the seminiferous scales. Another 

 fairly good example is the original of Phillips' figure (published 

 in the Geology of Oxford, Diag. xxxii.), preserved in the Oxford 

 Museum ; this shows the form of the cone-scales, as seen in side- 

 view, more clearly than most specimens. An imperfect cone from 

 the Forest Marble of "Wolverton in the Jermyn Street Museum is- 

 probably specifically identical with the Stonesfield type. The best 

 example of a male flower that I have seen is in the collection of 



Saporta (84), p. 600. 

 Schimper (70), p. 333. 



