1 8 INTRODUCTION'. 



map shows the position of the most important localities in this 

 part of the coast from which Lower Oolite plants have heen 

 obtained. 



The sketch-map shown in Fig. 1 is a simplified form of part of the 

 larger map published in the volume of the International Geological 

 Congress of 1888. While illustrating the relation of the Estuarine 

 Series of the Inferior Oolite (Bajocian) to the Middle and Upper 

 Oolite and to the Cretaceous rocks, it marks the position of the 

 chief localities from which the fossil plants dealt with in the 

 following pages have heen obtained. 



The moorlands and bold headlands of North-East Yorkshire 

 constitute an elevated region which is bounded on the west by 

 the low-lying Triassic plain of Central Yorkshire. Geologically 

 this district is marked off from the other Jurassic areas by well- 

 defined characters ; the rocks composing it are chiefly arenaceous, 

 with some Oolitic limestones and ironstones and a few thin seams 

 of coal. The occurrence of some subordinate marine beds affords 

 evidence of the frequent oscillations of level in this part of 

 England during the Jurassic period. Broadly speaking, the East 

 Yorkshire rocks of Lower Oolite age consist of three important 

 Estuarine Series separated from one another by thin bands con- 

 taining marine fossils. The following classification illustrates the 

 relative positions of these two types of sediments : 



fCornbrash. 



Upper Estuarine Series. 

 Scarborough or Grey Limestone Series. 

 LOWER OOLITE. { Middle Estuarine Series. 

 Millepore Series. 

 Lower Estuarine Series. 

 .The Dogger and Blea Wyke beds. 



These Lower Oolite rocks of England are correlated with part of 

 the Middle or Brown Jura of Germany (L. von Buch and Quenstedt ; 

 = Dogger of Oppel), and with the Bathonian and Bajocian of 

 French geologists. 1 



The Yorkshire Dogger, exposed in the cliff sections of Blea 

 "Wyke, High Whitby, Saltwick, and elsewhere, forms the lowest 

 member of the Lower Oolite rocks ; it is a littoral formation, 



1 Fox-Strangways (88), p. 132; Kayser (95), p. 238. 



