154 PROF. 0. T. JOXEs OX [vol. Ixxvii, 



There is some difference of opinion as to the position to be 

 assigned to the JRastrifes-mciximiis Zone. Charles Lapworth, Miss 

 Elles, and Dame Ethel Shakespear advocate its inclusion with the 

 overlying group, and their opinion is adopted in the foregoing 

 scheme. In the Lake District its affinities seem to be closer with 

 the underlying than Avith the overlying group. There is reason 

 to believe that Basti'ifes linncei, which occurs frequently in the 

 upper part of the Birkhill Stage, has sometimes been mistaken for 

 S. maximns, and this may account for some of the differences of 

 opinion noted above. The only district in Central Wales where 

 H. maxinms has been identified with certainty is in the Twymyn 

 Valley (Tarannon), where its affinities are clearly with the over- 

 h'ing beds. There is some doubt also about the position of the 

 zone of JMesogrcqjtus luodestvs, as this form has been quoted from 

 most horizons, from the zone of GJyptograptiis perscidphis to 

 that of Jlonograptiis iriangidaius. 



III. The GiRyAX Mixed Facies. 



A direct comparison of the shelh^ facies with the graptolite 

 scale can be made by reason of the magnificent development in 

 the Girvan district, Avhei'e shelly sandstones and mudstones alternate 

 with grey and black graptolitic shales, especially in the Lower 

 Yalentian. The classification given by Charles Lapworth ^ may 

 be slightly rearranged, in order to bring it into accordance with 

 the graptolitic scheme, as follows : — 



'Upper Yalentian Drum vork Group. 

 1 Bargany Group. 



I Penkill Group. 



Dailly Stage. i ^ ^ 



'' ° \^ Camregan Group. 



(4 



XJl 



Lower Yalentian 



Xew lands Stage. 



( Saugh-Hill Group, including the following sub- 

 divisions : — 



(a) Zone of MonogToptus sedgn•iclci{ = spini- 

 CJenls). 



(b) Saugh-Hill Sandstones (unfossiliferous). 



(c) Zone of Biplograptiis modestus. 



(f?) Woodland Conglomerate, Limestone, and 

 Mudstone. 



\ 



Mulloch-Hill Group, divided into : 



(a) Zone of Diplogro.ptus acuminatus. 



(b) Mulloch-Hill Sandstones and Conglo- 

 ^ merates. 



The Camregan Group, which was originally included in the 

 Xewlands stage, consists of yellow blue-hearted grits, with rare 

 BliynclioneUa, etc., which pass up into fossiliferous calcareous 

 flagstones and limestones. The latter pass gradually upwards 



1 Q. J. G. S. vol. xxxviii (1882) p. 537. 



