4 THE GEOLOGY OF TYTHERINGTON AND GROVESEND. 



this paper. It will be noted tliat the line between these 

 points does not run straight, but makes an S-like curve. 

 The section is therefore not at right angles ivith the strike 

 of the PalcBozoiG strata. We may conveniently divide it 

 Into the following sub-sections : — 



Sub-section 1. — From the 5J-mile post to 345 feet, where 

 the Mountain Limestone is cut off by a reversed fault. 

 The strata here dip from 30° to 34° S. by E., the line run- 

 ning N.W. 



Sub-section 2. — From the reversed fault to the 5J-mile 

 post, where the Palaeozoics, which emerge at 710 feet, are 

 overlain by the Basement Beds of the Trias. 



Sub-section 3. — From the 5J to the 5|-mile posts. The 

 line here runs nearly along the strike of the strata, which 

 dip 16° to 25° S. by E. to S.S.E 



Sub-section 4. — From the 5|-mile post to the mouth of 

 the Grovesend tunnel. The average dip is about 28° E.S.E., 

 and the line runs N.W. by N. 



Sub-section 5.— From the N.W. end of the Grovesend 

 tunnel to the end of the section. Old Bed Sandstone, with 

 varying dip, is overlain by solid conglomeratic Basement 

 Beds of the Trias. 



Sub-section 1. — The strata in this sub-section are well 

 exposed in Mr.. Hardwicke's quarry. To the south-west 

 they are overlain by Triassic beds. They may be thus 

 grouped : — 



Yellow and Blue Limestones, with Producti and ft. in. 



Lithostrotion . . . . . . . 60 



Silicious Limestone (2 beds) ; locally called " Fire- 

 stone " 9 3 



Blue Limestone with shaley partings {Lithostrotion 



and Producti) 75 9 



145 



