﻿Vol. 6 1.] BLEA WXKE BEDS IN NORTH-EAST YORKSHIRE. 445 



The foregoing list does not give us much information : Lingula 

 Beanii is still found, but in much diminished numbers, and 

 Ammonites Moorei can hardly be separated from A. aalensis. These 

 beds, therefore, may be regarded as merely a continuation of those 

 below, and by the officers of the Geological Survey both are grouped 

 together as the Grey Beds. This is a purely-lithological division, 

 but it seems to be borne out by the palaeontological evidence. 



(3) The Yellow Beds. 



The Grey Beds pass up, without any real break, into the Yellow 

 Beds, a thick series of ferruginous sandstones, with occasional 

 shaly bands and numerous lines of black pebbles. It is divided 

 into two parts by a very fossiliferous band, generally known as the 

 Terebratula-Bed, about 2 feet thick. 



The soft band at the base is not really very different from the 

 sandstone above ; but it is always deeply weathered out, and forms 

 a very conspicuous line in the cliffs. The rest of the series, up to 

 the Terebratula-Bed, is very uniform, and only varies slightly in 

 colour. The brown shaly bed above the Terebratula-Bed always 

 weathers out very deeply and makes, perhaps, the most marked 

 lithological break in the whole series, so much so that it is generally 

 taken as the dividing-line between the Blea Wyke Beds and the 

 Dogger proper. For various reasons, however, I have drawn this 

 line some 25 feet higher up. 



The fauna of these Yellow Beds is a rather large one, but the 

 fossils are always so badly preserved that, in many cases, specific 

 determination is almost or quite impossible. They are nearly all 

 in the form of ferruginous casts, in the lower 5 feet or so ; above 

 this fossils are rare, until we come to the Terebratula-Bed, where the 

 state of preservation is much better, but specimens are difficult to 

 -extract. In the published lists of fossils from this horizon there 

 exists a good deal of confusion, as no distinction has in most cases 

 been made between the Terebratula-Bed and the 25 feet of yellow 

 sandstone below it. In some cases, to make matters worse, the 

 fauna of these beds is lumped in with that of the Nerincea-Bed and 

 the Dogger proper of this and other localities. 



From the lower part of the sandstone I have obtained the fol- 

 lowing fossils : — 



Pentacrinus. 



BhynchoneUa subtetrahedra. 

 Avicula incsquivalvis. 

 Avicula substriata. 

 Pecten barbatus. 

 Pecten demissus. 

 Modiola cuneata. 



Astarte elegans. 

 Trigonia costata. 

 Trigonia Bamsayi. 

 Nerincea cingenda. 

 Cerithium sp. 

 Ammonites Moorei. 

 Ammonites (a smooth species). 



Besides these, there are a few lamellibranchs and other fossils of 

 uncertain position. 



