204 



MR. C. T. TRECHMAXN ON A MASS OF AXHYDRITE 



[June 1 9 13, 



Highest 

 Limestones. 



Hartlepool 



f Soft, white, porous, friable, well-"] 

 bedded limestones, showing 

 dendritic specks on fractured [ 

 surfaces. Calcite-lined geodes f 

 and small brown fiuorites j 



occur J 



Massive bedded ' roestone ' in part^ 



of section, enclosing large I or v f ■■, 

 flattened lenticles of powdery f - U 

 material ,.J 



Variable, hard and soft, white j 

 and yellow limestones. Fossils 

 generally obliterated, but some 



SeJiizodus scJilotheimi Gein. 

 Mytilus sept if er King. 



\~ SeJiizodus scJdotJieimi Gein. 

 PleuropJiorus costatus Brown. 

 Mytilus sept if er King. 



occur in the harder parts of the f 35 J \ % r f° Il f f ?f .J chL ,,. „ 

 ' Natica er. leibmtziana King. 



rock west of the 

 water 



new break- 



J 



I Small indeterminate gastero- 

 [_ poda. 



At Brunswick Brewery, Hartlepool, a boring was sunk to 100 

 feet in the limestone ; but no trace of anhydrite or gypsum, was 

 met with. 



In Victoria Dock the limestone was struck on the east side 

 of the dock, at a depth varying between 14 and 23 feet beneath 

 Boulder Clay ; but on the west side, 350 to 400 feet westwards, 

 the depth had increased to 36 and 50 feet. This is apparentlj r not 

 the dip of the beds, but represents the westward slope of the old 

 pre-Glacial ' slack ' or valley of which the anhydrite-mass forms 

 the floor. 



(2) West Hartlepool. 



Limestone of this outcrop is well exposed in a quarry near the 

 waterworks, and in the railway-cutting on the east. 

 The following section may be seen in the quarry : — 



Highest 



Limestones. 



f Thin, well-bedded layer 



yellow, decayed, extremely 

 porous limestones, interbedded 

 with hard bands a few inches 

 thick. Associated with these 

 are several beds, 1 to 2 feet 

 thick, of a soft yellow rock 

 showing a granular oolitic 

 structure. Traces of fossils 

 are abundant in some bands, 

 but are nearly obliterated J 



TJticJcness 

 in feet. 

 of soft,"" 



30 



C SeJiizodus scJilotJieinii Gein. 

 ■j Mytilus septifer King. 

 (^PleuropJiorus costatus Browi 



A boring at the waterworks shows that these beds continue 

 to a depth of 39 feet from the bottom of the quarry, when an 

 extremely hard limestone is met with, having a thickness of 9 feet. 

 Beneath this the details of the boring are unreliable, but it was 

 carried to 69 feet without encountering any trace of anhydrite or 

 gypsum. Samples of the above-mentioned limestone were found 



