18 DESCRIPTIVE CATALOGUE 



in diameter and nine feet in vertical height, and probably con- 

 siderably more. Specimens, as found, are often elliptical in shape 

 [which is possibly only partly due to crushing"!. In most speci- 

 mens the tissues are more or less petrified, and sections show 

 that the roots are dinrch, and the solcnosteles of the stems have 

 a ring of tracheids about 9 cells thick. 



HORIZON. Lower Greensand. 



LOCALITY. Potton. 



GENERAL DISTRIBUTION. Mainly found in the Wealden of 

 England, not common in the Lower Greensand. If the conti- 

 nental species T. S<- /////> /t.'ri is identical with 7'. erosa, as many 

 have assumed, it is fairly widely distributed in the continental 

 Lower Cretaceous. The genus is also represented in America 

 by a species which may or may not have to be included in 

 T. erosa when better specimens are known. 



TYPE. Semi-petrified " false-si em "recorded by Stokes, Webb 

 & Mantell, 1824, under the name Kn which 



appears now to be lost, though duplicates of Mantell'sure in the 

 Museum of Practical Geology. Jermyn Street. 



The assumption that the British plant A'/< M/ wa.s 



the same as YVw/>.s7-//x .SYA/////*.-/-/, founded by Cord a in \>l~>. 

 was based on the generic peculiarity and identity of the plants, 

 coupled with the very imj Mate of the knowledge of the 



species, owing to the poor petrifaction of the tissues. Hut even 

 if we assume, as is perleetly possible, that T. Xc1t'nni>< ri is the 

 same species as /,'//'//>;/ . the laws of priority of specific 



names necessitate the use of the name T. <v>a for both. 

 Prof. Seward (1894), who accepts the view of the identity of the 

 t\vo specimens (first promulgated by Vnger in his Genera et 

 Species Plant arum foss. 18 "><>). u- a's name and describes 



the British forms as T. Schimjteri. I consider that we have 

 not well enough preserved specimens to be suro whether or not 

 T. Schimperi and " Endng mites erosa" are identical: that if 

 they are, then tho species name erosa has priority, and both 

 must be described as Tempskija erosa ; in the present state 

 of our ignorance, however, it is well not to eliminate 

 T. Schimperi, but to keep the name as it was founded for 

 the continental specimens described by Corda. 



Regarding my addition of Mantell's name to the combination 

 of Stokes & Webb as authors of the paper describing the 



