52 MR. J. TV. GEEGOEY ON THE 



2. A thin-bedded finely-jointed shale, with some calcareous 



nodules and quartz veins ; along its lower margin it is some- 

 what baked and in places breeciated. 



3. An amygdaloidal diabase, cutting irregularly across the edges 



of the shale, which are sometimes curved up along the 

 junction. The exposed surface of the diabase is sometimes 

 variolitic. 



Fig. 4. — Junction of Variolitic Diahase and Black Shales ; in the 

 Crag, north of the pathivay to Heinersreuth. 



x' C 



Beds 1 and '2 belong to the Middle Devonian, and a])parently to the 

 lower part of this division (the " Unterschalstein mit Kalkgeoden" 

 of Giimbel). The Lower Devonian can be seen lower down the 

 slope, and especially at a pit in the " Nerei'tenschiefer " in the meadow 

 where the brook that drains the upper part of this valley takes 

 its source. 



The interpretation of this section appears to be somewhat as 

 follows : — A tongue from the diabase massif has projected for some 

 distance into the Devonian rocks, running approximately E.S.E., and 

 forming a ridge that extends as far as the Heinersreuth footpath. 

 The face of the intrusive diabase has been here exposed by removal 

 of the grits and shales during the denudation of the valley. 



The microscopic structure of this variolite must be compared with 

 that of the spheroidal knoll at Berncck. The rock consists of 

 a series of altered varioles in a transparent, light-green, slightly 



