ENDOGENITES EROSA. 289 



specimens are from a few inches to seven or eight 

 feet long, and the largest from twenty to thirty 

 inches in circumference. When imbedded in the 

 strata, a thick coat of lignite surrounds the stem ; 

 but this soon becomes friable, and falls off after 

 exposure to the air. The constituent substance 

 of the stems is a grey, compact, subcrystalline sand- 

 stone, and the external surface is traversed by fine 

 semicircular grooves and deep tubular furrows, 

 lined with minute quartz crystals ; a transverse 

 section exhibits the surface covered by small 

 pores, and a few large openings, the sections of 

 the tubes. From the eroded appearance of the 

 surface of the specimens, when deprived of their 

 carbonaceous investment, the name Endogenites 

 erosa was given to this fossil plant by Messrs. 

 Stokes and Webb, who described it from my 

 specimens, in the Geological Transactions, vol. i. 

 second series. Dr. Fitton * subsequently described 

 and figured a series of interesting specimens ob- 

 served by him in the strata at Hastings. In trans- 

 verse slices of these fossils, obscure indications of 

 circular bundles of vascular tissue were detected, 

 but (as in all my specimens from Tilgate Forest) 

 very few vestiges of organic structure were appa- 

 rent; the cavities exposed in the sections being 



* Geol. Twins, vol.iv. p. 172. 



