284 Reports and Proceedings — 



2. " The Devonian Eocks of South Devon." By W. A. E. Ussher, 

 Esq., E.G.S., of H.M. Geological Survey. 



This paper is the result of work done in continuation of the 

 labours of the late Mr. Champernowne, and refers particularly to 

 the area north of the Dart and east of Dartmoor. 



Owing to the complicated stratigraphy of the region, we have to 

 fall back upon such information as can be procured of the general 

 types of Upper, Middle, and Lower Devonian faunas ; for though 

 the lithological constituents of these three divisions are broadly 

 distinguishable, there are no definite lithological boundaries between 

 them. 



The Lower Devonian is mainly distinguished by the occurrence 

 of sandstone and grit, but the upper beds are shales passing into the 

 Middle Devonian slates. 



The Middle Devonian consists of limestones, and shaly limestones 

 upon slates, the latter representing the Calceolen-Schiefer, and con- 

 taining Spirifer speciosus. String ocephalus is found here and there 

 in the Middle Devonian Limestones. The upper part of the Middle 

 Devonian Limestones (with Lummaton fauna) passes into the 

 cuboides-beds of the Upper Devonian. The Upper Devonian con- 

 tains thin-bedded limestones, often concretionary, with chocolate-red 

 and pale greenish slates and mudstones. These beds correspond 

 to the Goniatiten-Schichten, Kramenzelstein and Knollenkalk of 

 Germany, and to the Cypridinen-Schiefer. 



In the Upper and Middle Devonian rocks we find a local preva- 

 lence of schalstein ard tuffs, breaking up the limestones. The slate 

 and sandstone type of Upper Devonian in North Devon appears to 

 give place southward to a purely slate type, possibly accompanied 

 by overlap of the Culm-measures. The author groups the South 

 Devon rocks under the following heads : — 



/ 1. Cypridinen-Schiefer. 

 Upper ... | 2. Goniatite-limestones and slates. 



( 3. Massive Limestones. 



/ 4. Ashprington Volcanic Series. 

 Middle... J 5. Middle Devonian Limestones. 



( 6. Eifelian slates and shaly limestone. 

 j (7. Slates and sandstones, generally red. 



■" { 8. Slates with hard grits. 



After discussing the relationship of the Lincombe and Warberry 

 beds and the New Cut Homalonotus-beds, the author notes the 

 discovery of Pleurodictyum by Mr. Whidborne in the railway-cutting 

 at Saltern Cove. He proves the Lower Devonian age of the 

 Cockington beds and their correlation with the Torquay Lower 

 Devonian by the discovery of fossils. He considers it probable, 

 though not certain, that the main mass of Meadfoot beds is below 

 the Lincombe, Warberry, and Cockington sandstones. 



The distribution of the Middle Devonian Limestones is described. 

 String ocephalus is found in limestones containing Bhynchonella 

 cuboides. The upper parts of the limestone-masses (East Ogwell, 

 Kingskerswell, Barton, Usham, etc.) may be Upper Devonian. The 

 massive limestones may terminate abruptly or pass laterally into 



