FROM THE SECONDARY ROCKS OF BRITAIN. 708 



half to an inch and three-quarters broad by three-quarters of an inch deep ; mesh » 



of the woody cylinder large, roundish, and frequent. 

 The smaller, equal-sized petioles and the more slender trunk at once distinguish this 

 species from M. nidiformis. I have seen only two specimens, and neither of them 

 show any indications of secondary axes. 



From the " Dirt-bed " in the Isle of Portland. [British Museum.] 



M. microphylla, Miq. Prodr. Syst. Cycad. p. 30. (Tab. LXIIL fig. 6.) 



1828. Cycadeoidea microphallus, Buckl. Proc. Geol. Soc. vol. i. p. 80; (1829) Trans. Gn.l. Soc. ser. ii. 



vol. ii. p. 397, t. 49. 

 1836. Cycadites microphyllus, Buckl. Geol. & Miner, p. 426, pi. 61. 

 1838. Zamites microphyllus, Presl, in Sternberg, Flora der Vorwelt, p. 196. 

 1849. Echinostipes microphyllus, Pomel, Amtl. Bericht Aachen, 1847, p. 340. 



Trunk cylindrical; permanent bases of the petioles small, lozenge-shaped, an inch broad 



by three-eighths of an inch deep ; meshes in the woody circle numerous and small. 

 This is the most abundant species in the » Dirt-bed " of the Isle of Port land. A xillan 

 branches abound in the stems. The description I have given of the branches in this gem 

 is taken from specimens of this species. 



From the « Dirt-bed" in the Isle of Portland. [British, Jermyn-Street, Geological- Society, ai.,1 

 other Museums.] 



M. pygmjea, Carr. 



1837. Cycadeoidea / 

 18-41 • Zamites 



Lindl. & Hutt 



Mas. Nat. Hist 



1849. Echinostipes pygmam, Pomel, Amtl. Bericht Aachen, 184", p. 347. 



Trunk small, subspherical ; bases of the petioles irregularly _ lozenge-shaped, ■ l.re.-e.ghths 



of an inch broad by one-eigbth deep, widely "^^Ji^WM* - 

 A single specimen of this species has been found, it ^as tut 3 

 showed L it was composed of the bases of the petioles placed ■ **>**£ *" 

 aud solid centre. It described as havmg a tubercle . »*— J Jj* * £ 



discover where this curious specimen is pieserveu, 



Philpotts at the time it was figured by Lindley and Hutton. 



From the Lias of Lyme Regis. 



M. incltjsa, sp. nov. (Tab. LXIIL fig. 2 et 3.) 



not been able to 



M. incltjsa, sp. nov. (Tab. LXIIL ng. a et o.j ^.^ ^ Lw 



Trunk small, cylindrical; medulla abundant ; wood - C ^ bundle s; bases of th<« petioh > 



ueneimtM by numerous small, ascending, vascu ar » ^ more than liVL 



lozenge-shaped, thrce-eighths of --^J".,, rf *e petid* 



eighth deep ; secondary branches large ; fcrnit mc i ftuits of BfH . 



>is species has the cylindrical stem of Mantelha wtth the mc 



penetrated 

 regularly 



This 

 nettites 



From the Potton Sands, Cambridgeshire 



Esq., F.G.S., York 



