206 



ME. C. T. TRECHMANN ON A MASS OF ANHYDRITE [June I C) I 3, 



in character. Slightly north of the fault the following seclioi 

 occurs : — 



Thickness 



Upper 

 Middle 



Limestones. 



60 No fossils. 



Massive white limestone, assum-" 

 ing a 'roestone' structure and 

 developing hard calcareous 

 spongj' breccias for some dis- 

 tance north of the fault. 

 Layer of small yellow brecciated 

 1 fragments, thinning out before 

 the fault is reached. 

 Thinly stratified limestone, very 

 I loosely compacted, showing 

 j traces of large lenticular in- 

 l_ elusions now removed 



Between the fault and the incoming Concretionary Series a. 

 well-defined space intervenes, filled with a soft collapsed mass of 

 comminuted white-and-yellow fragments of a fetid limestone. 

 The bedding is visible in part, and a band of limestone at the 

 base dips rapidly southwards ; this seemingly indicates that the 

 beds next encountered have been carried downwards. 



(3 b) Coast-Section south of Blackball Rocks. 



The coast-line between Cross Gill and the Targets at Hart is 

 occupied by the lower series of the Upper Limestones, here forming 

 two divisions, of which only the lower shows any concretionary 

 structure. In no case is that structure developed to the extent 

 observed in the Sunderland area. The section is as follows : — 



Fauna. 



conceetionaky 

 Limestone. 



Thickness 



in feet. 



f Thinly - bedded, well - stratified ^ 

 yellow limestones, frequently 

 brecciated and collapsed. Fos- 

 sils occur lying on a matted ± 3 J S ct£o*dus scMotheimi Gei 

 ground of rods of Filograna. , ) M j . f Km 



Sections of this fossil are 

 visible in the face of the cliff' as I 



small circular punctures J 



J Hard, fissile, fetid, flaggy lime- ~"| 



' stones with interstratified beds 

 developing concretionary, bo- 

 tryoidal, and cannon-ball struc- 

 tures. Associated with these 

 (as matrix of the concretions) 

 are soft, fetid, grey or brown 

 marly - looking l limestones, 

 occasionally massive, generally 

 much brecciated and collapsed. . _ 

 Base not seen. 



|>50 



(Filograna (?) permiana' 

 I King. 



■hizodus sclUotheimi (jem 

 I Mytilus septifer King. 

 {jfatica sp. 



fScJiisodus schlotheimi Gein. 

 j Mi/tilns septifer King. 

 J Slabs of concretionary lime- 

 j stone, with crowded masses 

 ! of testiferous specimens 

 (_ occur. 



1 Incorrectly described by early writers as 'marl' or 'marly limestone.' 

 It yields practically no clayey residue on solution, but much oily organic 

 matter. 



3 W. King, 'Monogr. Perm. Foss. Engl.' (Pal. Soc.) 1850, p. 56. 



