Vol. 69.] IN THE MAGNESIAN LIMESTONE AT HARTLEPOOL. 207 



(3 c) Coast-Section from Blackball Rocks to 

 Castle-Eden Dene. 



This section measures slightly over a rniie. The southern part 

 embodies a section of the Concretionary Series similar to that, already 

 described. The fault that brings down the concretionary beds 

 occurs a short distance north of Blackball Hocks. It is apparently of 

 slightly greater throw than the corresponding fault on the south. 



The northern part of the section, across and beyond the mouth of 

 Castle-Eden Dene, exposes the following beds: — 



Thickness in feet. Fauna. 



"Very soft, white and yellow,""] 



powdeiy limestones, associated 



with a ' roestone ' well seen on | 



the shore. Both are pierced j 



and interbanded with irregular | 



masses of yellow, crystalline, )- 25 (?) Schizodus sp. 

 calcareous material which re- 

 tains in part the ' roestone ' 

 structure. The oolitic grains 

 are filled with aggregates of 

 brown fluorite-crystals J 



Owing to the complication of the cliff-section by glacial action 

 and fallen sand and clay, it is impossible to ascertain the thickness- 

 of either these or the concretionary beds. 



Uppermost 

 Limestones, ' 



(4) Hesleden Dene. 



A post-Glacial ravine extending in a more or less east-and-west 

 direction for a distance of about 4 miles. The stream has cut a 

 gorge in the limestone, laying bare a good and continuous section of 

 the Middle and Upper Magnesian Limestones for about 3 miles. 

 The limestone is first met with about half a mile from the dene 

 mouth. Between the two railway-viaducts which cross the dene, 

 the stream passes through a gorge where the following section of 

 Upper Shell-Limestone is exposed, and can be studied both in the 

 gorge and in an old quarry in the dene close by : — 



Thickness in feet. Fauna. 



f Hard, bedded, Shell-Limestones. "") 

 1 Thinly-bedded limestone in part 

 I of the section. 

 I Interbedded conglomerates 



Upper | rounded, or angular and much j 

 Shell- -{ broken up. The masses consist }■ 35 

 Limestones. I of typical, fine-grained, compact 

 I Shell-Limestone. 



Hard limestones, more or less 

 | bedded, showing locally much | 

 L_ internal deformation J 



Prevailing dip of the beds = about 5° east-south-eastwards. 



These beds very closely resemble the Shell-Limestone Con- 

 glomerate of Blackhall Rocks and are probably equivalent thereto. 

 They very likely owe their existence here to a fault west of the 

 gorge which cannot now be traced, but may lie beneath the railway- 

 embankment. 



Dwarfed and impoverished 

 Shell - Limestone fauna 

 similar to, but scantier 

 than, that of Blackhall 

 Rocks. 



