270 PEOFS. LLOYD MOEGAIf Al^TD REYNOLDS ON THE [Aug. I9OI, 



II. DESCEIPTlOIf OF THE ExPOSUEES. 



An examination of the map (see PI. X) shows that the igneous 

 rocks occur, broadly speaking, on two horizons — a lower to the east 

 and north-east, and an upper to the west and south-west. Both 

 trap-horizons are represented at Charfield Green. Farther north 

 the Silurian strata are overlain unconformably by Keuper Marls. 

 Beyond this the trap of the lower horizon courses from Damery 

 Bridge through Mickle Wood to Woodford Green, and then curves 

 round along the northern rim of the basin to Middle Mill, beyond 

 which it cannot be traced. The trap of the upper horizon appears 

 at Avening Green, and probably courses through Crockley's Farm 

 (where it was proved by the Earl of Ducie) to DanieFs Wood. 

 According to the Surveyors' mapping, a fault marks its north-eastern 

 boundary. We now propose to deal with these exposures in detail. 



(a) The Charfield- Green Exposures. 



The two bands of trap are here seen, one on each side of the Midland 

 Railway, Charfield Station being situate near the middle of their 

 course. Their direction is nearly north-north-west and south- 

 south-east, approximately parallel to the railway-line. At both 

 ends they are overlapped by Keuper. 



(1) The easterly or lower band. — Theonly definite exposures 

 of this band that we have been able to detect are seen in the bed 

 of the little stream which, crossing: the railway between the village 

 and Hillhouse Earm, meets the Little Avon west of Elbury Hill. 

 But in the Geological Survey Map a more extensive band is shown. 



Between the line and a little cottage on the bank of the stream 

 are fairly good exposures of an unfossiliferous red sandstone, pro- 

 bably of Llandovery age, with a dip to west 20° south, decreasing 

 as one proceeds eastward from 37° to 15°. Behind the cottage, 

 in the corner of the field, is a good exposure of the trap, a 

 fairly-fresh, compact, non-amygdaloidal rock. In the stream near 

 by, the trap is also clearly seen, and is here markedly amyg- 

 daloidal, some of the original vesicular cavities being filled with a 

 black specular-looking chJoritic mineral. The contact of the trap 

 with sedimentary beds is unfortunately obscured, and no sedimen- 

 taries are seen in the stream-bed beyond and below the trap. But 

 1 50 vards farther north, by the hedge in the next field, we obtained 

 Llandovery fossils, though not actually in situ. 



The characteristically amygdaloidal nature of the trap in the 

 stream-bed suggests that it is a contemporaneous lava, but these 

 exposures show little upon which definite conclusions can be based. 



(2) The westerly or upper band. — There is a good exposure 

 of the trap in an old quarry (Cullimore's) lying close to the railway- 

 line north-east of Poolfield Earm.^ It is here in parts compact, in 



^ A section in this quarry is figured by Murcbison, in the 'Silurian System' 

 1839, p. 459, wbicb shows bands of indurated sbale and thin curved masses of 

 shelly sandstone and of gritty impure hmestone included within the mass of 

 the trap. No such inclusions are now visible. 



