222 PEOF. S. H. EEYNOLDS ON A SILT7RIAN [May I907, 



evidence of the presence of trap has been found, and it appears 

 that the band is interrupted, as indicated in the Geological-Survey 

 map. 



The Downhead and Tadhill mass.— Eastward of this 

 interruption, the westernmost spot where trap occurs is at the 

 corner of a field 300 yards south-west of Tadhill Farm, where 

 its presence was proved by trenching. Unmistakable evidence of 

 the occurrence of the trap is afforded by abundant debris along the 

 hedge-banks in the fields to the south-east of Tadhill Farm ; and 

 at one spot it is found in situ. A little farther east is a considerable 

 exposure in a field, and from this point onwards abundant debris 

 was found as far as the large new quarry at Downhead, where the 

 trap is finely exposed and of the same general type as at Moon's 

 Hill and Sunnyhill. Trap-fragments may be found along the 

 hedge-banks almost everywhere in the area between Tadhill House, 

 Luxton's Lane, and Downhead Quarry. Trap is further exposed 

 in Luxton's Lane, north-west of Manor Farm ; and fragments were 

 found in a field to the east of the lane. 



(2) The normal Tuffs and the associated Fossiliferous Rocks. 



Though tuff-debris has been met with at several points (indicated 

 in the map, fig. 1, p. 220) in the western part of the area west- 

 south-west of the ' Waggon & Horses ' Inn, the material may have 

 been derived from the matrix of the coarse ashy conglomerate. 

 Tuff-debris was also noted at a little pond in a field west of Long- 

 Cross Bottom. It is not, however, until Sunnyhill Quarry (Stoke 

 Lane) is reached, that the tuff is seen in situ ; here is exposed the 

 finest and most interesting section in the whole area : the following 

 beds are seen (fig. 3, p. 225) : — 



Thickness in feet. 

 8. Andesite to top of section. 



7. Rather coarse tuff and shaly material about 25 



6. Andesite about 25 



5. Tuff, mainly rather coarse 16| 



4. Very fine red ash and ashy clay with many small lapilli, ) o 



passing down into a slightly-coarser red ash J 



3. Thickly-bedded, and in the main rather coarse tuff, dark j no 



when fresh, but weathering pale f 



2. Very fine red ash , 3 



1. Much weathered, rather fine tuff, mainly soft and yellow, 1 ^ 

 but with harder bands containing Silurian fossils } 



Total thickness of ashy series seen 160^ 



The dip of this series is 40 to 45 degrees IN". 20° W., so as to give 

 an east-north-easterly strike, which agrees in the main with that 

 of the igneous series as a whole,and is not very far removed from 

 the strike of the chief axis of the Eastern Mendips. 



