8 PROCEEDIXGS OF THE GEOLOGICAL SOCIETY. 



being one continuous series, they occur folded in more or less 

 broken troughs. In the Morte Slates, previousl}' considered un- 

 fossiliferous, the Author found a Lingula, and he believes that these 

 slates are the oldest rocks in the area, and formed the floor upon 

 which the Devonian Ilocks were deposited unconformably. As the 

 result of movements in the Earth's crust, the Morte Slates have 

 been brought to the surface and thrust over much newer rocks, 

 ])roducing a deceptive appearance of overlying the latter conformably. 

 The Morte Slates mark the dividing line between the two main 

 troughs. On the north side in ascending order are the Hangman 

 (or Lynton), Combe-Martin Bay, and Ilfracombe Eeds, and on the 

 south side the Pickwell-Down, Baggy-Point, and Pilton Beds. 

 Those on the south side of the Morte Slates are, the Author 

 believes, a repetition of the beds on the north side. The palaeon- 

 tological evidence is not antagonistic to this view, for an analysis of 

 the Brachiopoda, the only group of fossils in the beds on the south 

 side which hitherto have been systematically examined, shows that 

 of the twenty species mentioned by Mr. Davidson and others as 

 occurring in the Pickwell-Down, Baggy-Point, and Pilton Beds 

 (the so-called Upper-Devonian Rocks), no less than thirteen have 

 already been found in the Middle- or Lower-Devonian Rocks on 

 the north side of the Morte Slates. Pour others are recognized 

 Middle-Devonian species in other areas ; and the three remaining 

 are either doubtful species or have a great vertical range. These 

 facts show that the so-called Upper-Devonian Rocks in this area do 

 not contain a distinguishing fauna of any importance; and the 

 stratigraphical evidence is opposed to the view that they are a series 

 of rocks distinct from those on the north side of the Morte Slates, 

 which have been classed as Middle and Lower Devonian. 



Discussion. 



Mr. T. Roberts began with the stratigraphical evidence. The 

 Lhi^/ula found in the Morte Slates gave no evidence of age ; and he 

 believed the high dip in the Morte Slates was of no value as differ- 

 entiating those slates from the other beds. Certain zones of the 

 Hangman Beds are crowded with fossils, and these are not found in 

 the Pickwell-Down region. He objected to the Brachiopods onl)' 

 being chosen for purposes of correlation, and thought the doubtful 

 specimens told either way. The Baggy and Pilton Beds, according 

 to the Author, are similar to those associated with StringocepJialus 

 Burtini. Twelve out of nineteen species of Brachiopods in the 

 Baggy and Pilton Beds pass into the Carboniferous, whilst only 

 five pass down into the Ilfracombe series. Phacops latifrons is 

 stated to be abundant in Middle Devonian of South Devon ; but 

 many of these are probably Phacoj)S hatracheus. Ph. latifrons had 

 been found on the Continent in beds of Lower-, Middle-, and Upper- 

 Devonian age. He had analyzed the Baggy and Pilton fossils, and 

 out of the 1 20 species he had been able to give generic names only 



