246 ME. C. T. TKECHMAKF ON THE LITHOLOGT [June 1914, 



everywhere highly changed, being thereby distinguishable from 

 the underlying Lower Beds. Original patches occur in most of the 

 sections, and yield a scanty but very constant fauna. Unaltered 

 beds are frequently massive, and very regularly stratified. The 

 segregations often follow the lines of stratification ; and 

 subsequent removal of the powdery dolomite accentuates the 

 appearance of bedding, leading to irregularity and brecciation. 



Castle Eden Dene, near Devil's Bridge. — LYIII. Fine- 

 grained, well-bedded, friable, yellow, slightly fetid rock. Well- 

 preserved casts of Astarte vallisneriana and other fossils occur. 



Castle Eden Dene, near White Rock. — LIX. Thinly- 

 bedded, fine-grained yellow rock, interstratified with segregated 

 material. Flat hollow spaces occur along the bedding-planes, with 

 casts of serpulae, ostracods, and small bivalves. 



Sections of both these rocks (LYIII & LIX) exhibit loosely- 

 compacted allotriomorphic dolomite-grains, with included matter. 

 Staining shows a faint coloration round the margins of the grains. 

 A faint general stain suggests that the inclusions are largely calcite, 

 a surmise which is confirmed on examination with a higher power. 

 Occasional calcite-groups occur. 



LVIII. LIX. 



Insoluble residue 0*16 0*05 



Fe.,0;,, etc 0'12 0-41 



CaCO, 54-50 55-14 



MgCOg 45-60 44-93 



S0 3 tr. 0-10 



Totals 100-38 100-63 



Calcite 0*21 1-65 



Dolomite 99'89 98'42 



Tuthill Quarry, near Ha swell. — A small patch of original 

 rock occurs near the base of a very big quarry-section of highly- 

 segregated beds. Powdery material has largely disappeared towards 

 the upper part of the section. Its position cannot be far above the 

 top of the Lower Beds. Casts of the usual fossils occur in plenty. 



LX. Extremely-friable yellow oolite. 



LXI. Extremely-friable, fine-grained, non-oolitic rock, in rather 

 massive beds. 



LX. LXI. 



Insoluble residue 0*02 0-12 



Fe.A, etc 0-57 0-36 



CaC0 3 56-24 55-35 



MgC0 3 44-05 44-75 



S0 3 0-07 0-02 



Totals 100-95 100-60 



Calcite 3*80 2-07 



Dolomite 96*49 98'03 



