•62 JET. 



51,447. Longitudinal radial section ; several" deep meduUaiy rays. 

 51,497. Large and badly preserved transverse section. 



51.757. A transverse section of inferior preservation ; possibly 

 referable to Cttpressinoxyhn Barleri. 



Near Wbitby, Upper Lias. Bryson Coll. 



COOTFEEOUS WOOD OF DOUBTFUL POSITION. 



51,500. Tangential section, including a parenchymatous region 

 in tte neighbourbood of a branch. 



Whitby. Bryson Coll. 



51,694. Transverse section, showing exceptionally narrow 

 rings of growth ; much crushed. 



Staithes. Bryson Coll. 



51.758. Badly preserved radial section, labelled " Fossil tree, 

 Whitby, Tertiary." Probably a piece of Liassic wood. 



Bryson Coll. 



JET. 



(Plate VIII. ; Text-figs. 5-7.) 



The name 'jet' is said to be derived from the river Gagas in 

 Lycia, where the substance was obtained. The following passage 

 from Pliny is of interest in reference to the origin of the term jet 

 and as regards its supposed properties : — 



" Gagates lapis nomen habet loci et amnis Gagis Lyciae. Aiunt 

 €t in LeucoUa expelli mari atque intra xii stadia colligi. Niger 

 ■est, planus, pumicosus, levis, non multum a ligno differens, fragilis, 

 odore, si teratur, gravis. FictHia ex eo scripta non delentur ; cum 

 uritur, odorem sulphureum reddit; mirumque, accenditur aqua, 

 oleo restinguitur. Fugat serpentes ita recreatque volvse strangu- 

 lationes. Deprendit sonticum morbum et virginitatem sufGltus. 

 Idem ex vino decootus dentibus medetur strimisque cerse per- 

 mixtus. Hoc dicuntur uti Magi in ea, quam vocant axiaomantiam, 

 et peruri negant, si eventurum sit quod aliquis optet." ^ 



1 Pliny, Nat. Hist. Book xxxvi. 34, 141. 



