24 



IIASSIC SYSTEM. 



A detailed account of the Lias of Yorkshire was published iu 

 1876 by Tate & Blake ; ' they mention the following plants :— 



Driftwood from various localities and horizons. 



Tecopteris, sp., from the Ammonites anguUtiis zone. 



Ilquisetites {?) Hassicum from the A. Bucklandi zone. 



Pachyphyllum peregrinum from the zones of A. annuUtus and A. serpentinus. 



Peuce Suttoniana | ^^^^ ^^^ j^j^^_ ^l^j^^y 



F. LmdUyana ) 



Chordophyllites cicatricostis ] 



ChordophyUites oicatricosus | ^^^^ ^^ ^_ ^^^^^^^ 

 NiiUiporites furcillatm ) 



These supposed Algee are too obscure to be determined, and 

 cannot be accepted as trustworthy records of Liassic plants. 



The account given by Tate & Blake of the jet from the Upper 

 Lias beds is referred to in the sequel. The two species of 

 Conifers, Peuce JSuttoniana and P. LinAleyana, were described 

 and figured by Witham in his well-known book of 1833.' Much 

 inioi-mation as to the Liassic rocks of Yorkshire is given by 

 Pox-Strangways ' in a Survey memoir published in 1892; the 

 foUowing classification is taken from that volume : — 



LIAS OF YOEKSHIEE. 



iStriatulm heds 

 Alum shale 

 Jet shales 

 Grey shales 



Middle Lias. 



f Ironstone series 

 I Sandy series 



Upper series 

 nodules ... 



LcwEB Lias. 



with Ironstone 



Lower series "with sandy and 

 marly bands 



. Zone of Ammonites jurmsis. 



,, A. communis. 



„ A. serpentinus. 



,, A. annulatus. 



,, A. spinatus. 



,, A. margaritattfs. 



,, A. capricorniis. 



,, A. Jamesoni. 



,, A. annatus. 



,, A. oxynotus. 



A. Bucklandi. 

 A. angulatits. 

 A. planorhis. 



1 Tate & Blake (76). 



2 Witham (33). 



' Fox-Strangways (92). 



