()38 Palaeontologie. 



In the Introduction, a short discussion is devoted to the 

 transition from the Palaeozoic to the Mesozoic type of flora, 

 and the extent of the evidence as to the flora of the period, 

 here treated, in different parts of the world. After describing 

 some seeds (Carpollthes sp.) of K e u p e r äge, a few species 

 of Triassic age are discussed. Eqiiisetites Muensteri Sternb., 

 Lycopodites lanceolatiis (Brodie), Clathropteris platyphylla 

 (Göpp.), Carpollthes sp., and ? Araiicarites sp.. are figured and 

 described. 



The plant-remains from the English Lias are more 

 numerous. The more important are Thlnnfeldla rhomboldalls 

 Ett., Cycadltes rectangnlaris Brauns, Otozamltes obtusus (L. 

 and H.), and Paglophyllum peregrlnnm (L. and H.). Two 

 Cycadean stems, Cycadeoldea (Yatesla) gracllls (Carr.) and ? 

 Cycadeoldea pygmaea (L. and H.i are described and figured, 

 and the structure of some Coniferous vvoods, Araucarloxylon 

 Llndlell (Witham) and a new species Cupresslnoxylon Barberl, 

 is illustrated by several microphotographs. 



This section also includes a discussion on the genus Thlnn- 

 feldla which is regarded as being, in all probability, a fern. 



A special section is devoted to an account of the nature 

 of Jet, which occurs in the upper Lias ofWhitby on the 

 Yorkshire coast. After an historical summary of the various 

 vievvs which have been held as to the origin of this substance, 

 the conclusion is expressed, as the result of a re-examination 

 of Whitby jet, that, in all probability, it has been produced 

 in large measure by the alteration of wood of the Araucarlan 

 type. Undoubted Araucarloxylon wood occurs in the Lias 

 rocks in association with jet, and in microscopic sections of the 

 latter, traces of the tissues can still be recognised. A number 

 of microphotographs, showing coniferous wood partly coiiverted 

 into jet, illustrate this section. 



The Inferior Ooiite plants from Gloucestershire, Lin- 

 colnshire, and some other English districts, are few in 

 number. Among these, Laccopterls Woodwardl (Leck.), Wll- 

 llamsonla Bucklandl {Ung.J, W. pecten (Phill.), and Arau- 

 carltes sphaerocarpus Carr. are the best preserved. A more 

 important horizon is that occupied in the Great Ooiite of 

 Oxfordshire by the Stonesfield Slate, the flora of which 

 is fully dealt with in this volume. The most abundant Stones- 

 field plants are Zamltes megaphyllus 'Phill.) and Thultes ex- 

 pansus Sternb. Among the other species described are Taenl- 

 opterls vlttata Brong. , Sagenopterls Phlllipsl (Brong.), 

 Gingko dlgltata (Brong.), Cycadeoldea squaniosa (Brong.), 

 Ctenls latlfolla (Brong.;, and Carpollthes dlospyrlformls sp. 

 Two new species Sphenozamltes Belli, and Podozamltes stones- 

 fleldensls are figured and described. 



Perhaps the most interesting specimen, botanically, is that 

 described as Phyllltes sp. Two impressions of this leaf from 

 Stonesfield are figured. It is oval in shape and petiolate. 



