632 



Frof. W. Keeping — Geology of Aherystioyth. 



Suggested Comparison of the Succession of Formations in North Devon 

 AND the South of Ireland : — 

 Descending Series. 

 North Devon. South of Ireland. 



Is a! fj. Pilton and Barnstaple Beds. — Cal-^ 



pq H ^z^ careens sandstones, grey shales I Lower Carboniferous Slate and 



^•^ fl I and slates with nodular lime- | 



^ p "§ ^ stones. Fossils — Marine. )> 



^ § ^ \ a. Baqgy and Marwood Slates. — 1 



^ ^ ^^ I Slates and sandstones -with Cu- \ 



^ I. cullcea, etc. J 



" Coomhola Grits." — Grey and 

 olive green slates and grits 

 with calcareous bands. Cu- 

 cullcea and other fossils. 



f5. 



i5 u 



■^.^< 



Drayton and Slade Beds. — Green- 

 ish and yellowish sandstones 

 (passage beds). 



PicJcwell Down Sandstone. — Eed 

 micaceous sandstones, shales, 

 and conglomerates. 



Upper Old Med Sandstone (" Yel- 

 low sandstone, Griffith"). — 

 Yellow and greyish flaggy 

 sandstones, with Anodonta 

 JuJcesii, Adiantites, etc., and 

 fish. 



Old Eed Sandstone. — Eed and 

 brownish-red sandstone with 

 bands of shale and conglomer- 

 ate at base. 



r^. 



m- 



Mortehoe Group. — Grey and purple 'j 



glossy slates, etc. 

 Ilfracomhe Group. — Shales and 



slates with limestones, with 



String ocephalus, etc 



Not represented in Ireland. 



<( b. Hangman Grits. — Eed and grey )- Great gap and unconformity at this 



^ (a. 



S \ 



^ I 

 CO I. 



II.- 



grits, shales, and sandstones 

 Lynton Slates. — Gritty slates, 

 shales, and sandstones, with 

 fossils. Spirifera, Orthis, Fene- 

 stella, Bellerophon, etc. J 



Linton Sandstone {Foreland 

 Group). — Eeddish, green, and 

 purple grits and slates. — Plants ? 

 " Fucpids," and Annelid bur- 

 rows only. 



stage. 



Dingle Beds and Glengarriff 

 Grits. — Greenish Grits, red 

 and purple slates and con- 

 glomerates. Plant-like mark- 

 ings and Annelid buiTOws. 



-Notes on the Geology of the Neighbourhood of 

 Aberystwyth. 



By Walter Keeping, B.A., F.G.S. ; 



Professor of Geology in the University College of "Wales. 



N England and Wales there is scarcely any area whose geological 

 structure is so little known as the neighbourhood of Aberystwyth, 

 Every year a stream of geologists passes through the northern parts 

 of the Principality, through the varied old-volcanic districts of 

 Snowdon and Cader Idris, and the rich collecting grounds of the 

 Berwyns : and another such stream takes its course to the southern 

 borders along the far west Pembrokeshire coasts, being guided by 

 the careful work of Dr. Hicks. The border counties too are in 

 many places attractive enough, for there it was that Murchison first 

 saw the order of the Silurian rocks, and there also the best-preserved 

 fossils are foimd. Llandeilo, Builth, Woolhope, May Hill, Malvern, 

 and Wenlock have long yielded rich harvests to palgeontologists. 



