3l8 JURASSIC. 



appearance which the rock assumes owing to the rounding off 

 of the huge oblong blocks, produced by the arrangement of the 

 jointing ; but the word Dogger, in the patois of the district, is 

 applied to any rounded stone. The beds may be studied at Peak 

 (Blue Wykc),' Glaisdale, Sandsend, High Whitby, and Saltwick. 

 (See Fig. 47.) 



The Upper Lias passes gradually upwards into the beds above, 

 which are classed as follows : — 



Feet. 



i Yellow sandstone and ironstones (Dogger) including the 

 Nerinaea Bed (A^. ciiigcnda) 30 



Yellow sands and sandstone, with Terebratula Bed [T. 

 siibmaxillatd) 20 to 25 



p, I Grey sands and Sandstones, containing a Serpula Bed, 



■^ , \ and Lingula Bed (A. Beaiiii) 20 to 25 



c \ j Passage beds, Sandy Shales yielding ^wwi?«/toj/;'/a/«///j (Striatulus 

 I Beds). Zone, oi A/iinionitcs yureiisis. 



The Dogger, according to Mr. W. H. Hudleston, contains 

 GerviUia iortuosa, G. lata, Macrodon Hirsoncnsis, Trigonia dentictdata, 

 T. v-costata, T. spinidosa, Cardium acutangulum, Astarte elcgans, 

 Ceromya Bajociana, and Rhynchonella siibobsoleta. In the sands 

 beneath occur Amni07iites Aaletisis, A. coviensis, Discina rcflexa, 

 Rhyjichotiella cynocephala, and Terebratula trilineata} 



The Dogger is placed on the horizon of the Inferior Oolite, in 

 the zone of Ammonites Murchisoncc, so that the sands below are 

 probably homotaxial with the Midford Sands, and represent the 

 zone of ^. opalinus. 



The Dogger itself has been much worked for iron-ore, which contains from 30 

 to 50 per cent, of the metal. Tlie magnetic iron-ore of Rosedale is worked in this 

 series ; and Prof. PhilHps considers that tliis ore and those of Thirsk and Kirkham 

 are the equivalents of the Northamptonshire iron-ores.'' 



Lower Estuarine Series. 



This series was described by Phillips, in 1829, as the Lower 

 Carbonaceous Sandstone and Shale. It rests upon the Dogger, 

 and comprises alternating beds of sands, false-bedded sandstone, 

 and shale, with cement-stone, oolitic ironstone, thin seams of 

 impure coal, and much carbonaceous matter. It attains a thickness 

 of from 100 to 280 feet. The beds, as a rule, contain no marine 

 shells, but many plant-remains, including Za??i{a gigas, Eqinsetites 

 columnare, Otopteris, etc. One marine bed with Pholadomya has been 

 noticed by Mr. Hudleston ; this may be about the same horizon as 

 the Eller Beck Bed, first noticed by Mr. G. Barrow in EUer Beck, 



' Wyke means a hollow of the sea-coast or small bay. The locality is some- 

 times termed Blue Wick and Blea WylvC. 



- G. Mag. 18S2, p. 147, P. Geol. Assoc, iii. 293 ; Wright, Q. J. xvi. i. 



^ Geol. Eskdale, Rosedale, etc., by C. F. Strangways, C. Reid, and G. 

 Barrow, p. 21. 



