128 DEVONIAN. 



They comprise yellowish and greenish flags and shales, which 

 pass downwards into purple sandy shales and grits. The Drayton 

 and Slade Beds, so termed by Prof. Hull, take their name from 

 farmsteads north of the Barle, north-west of Dulverton.^ The beds 

 here exposed were originally described by Jukes as greenish- 

 yellow, rather soft, earthy sandstones, often splitting into flags." 

 They belong to the Pickwell Down Sandstones. 



Hcematite occurs here and there in the Pickwell Down Sandstones. 



Baggy and Marwood Beds. 



These beds take their names from Baggy Point, south of Morte 

 Bay, and Marwood, north of Barnstaple. 



They consist in the upper part of micaceous flaggy sandstones 

 and grits, characterized, according to Mr. T. M. Hall, by Ciicullcea 

 irapczium — hence these beds are known as the Cucullffia zone or 

 grit. Imprints of rain-drops are met with on the surfaces of the 

 beds. The lower part of the series is made up of green and grey 

 slates with Lingida squa?ni/oriuis. Mr. Ussher informs me that the 

 relative positions of these fossiliferous zones are reversed as the 

 beds are traced eastwards. 



Among other fossils are Aviciila Damnoniensis, Rhynchonella 

 laticosta, Stivphalosm producloidcs, Spirifcra disjiuida, etc. 



In the sandstones of Sloly Quarry, east of Marwood, remains 

 of Lepidodendron or Knorria, Calatia'tes, and Adiuutites have been 

 found; plants which foreshadow the vegetation of the Carboniferous 

 period. 



The total thickness of the series is not known. 



By Mr. Etheridge the beds of Marwood are placed at the 

 base, and the Baggy beds at the top of the series.^ The Marwood 

 beds were taken as the uppermost Devonian by Sedgwick and 

 Murchison, and were classed as the Barnstaple or Petherwin 

 Group.'' Mr. J. W. Salter grouped the INIarwood Beds with the 

 Upper Old Red Sandstone.^ 



Pilton Beds. 



The Pilton Beds, to which the name Pilton Group was applied 

 by John Phillips, take their name from Pilton, near Barnstaple. 

 The beds consist of greenish-grey slates and shales, with beds of 

 calcareous sandstone or gritty beds, and occasional nodular bands 

 of limestone. The thickness is not known. 



1 G. Mag. 1878, p. 532 ; 1879, p. 94. 



2 Additional Notes 011 the Grouping of the Rocks in North Devon and West 

 Somerset, p. 5- 



3 Manual of Geology, p. 171. The Brushford Beds, mentioned by Mr. Etheridge, 

 belong to the Pilton Beds. 



4 Q. J. viii. 3. * Q. J. xix. 478. 



