Fig. 11.— Vertical section of the Pont Erwyd Stage, slowing the 

 distribution of the more important graptolites. 



Castelt, 



Gboup 



(Be). 



250 feet. 



Eheidol 

 Gboup 



(Bb). 



About 

 400 feet. 



N 2 -^ 



o ■> - 

 • 2; © 



o b*5 



N o.s 



. s: ^ 



ElSTEDDFA 

 GrEOUP 



(Ba). 



C5 



Blue flags with 



gritty stripes. 

 Smooth blue flags : 



Monograptus sedgwicki 



Mastri'es maxim ux, Monograpt its sedgwicki, 31. ef. nudus, 



M. decipiena, Climacograptus /tughesi, etc. 

 M. tenuis and M. sedgwicki abundant ; also Glypto- 

 -1 graptus serratus var. barbatus, etc. 

 Cephalograptus cometa, M. lobiferus, M. limalulus, M. 

 convolutus var., M. ansulosus, Rastrltes hgbridas, etc. 

 M. decipiens, M. limatulus, M. lobiferus, M. regularis, 

 Shale band. [Eastrites hybriaus, ete. 



M. convolutus abundant, with 31. limatulus. M. ansu- 

 Monograptus convolutus. [losus, ete. 



31. leptotheca, 31. ef. millipedia, 31. arguius, M. communis 

 -j var., M. gregarius, Mesogr. magnus, Climacogr. hughesi, ete. 

 Ve.iogr.magn us, Monngr. com ■ iiunis var., 31. urgutus, etc. 

 ~M. triangulatus, 31. communis. Sast. appro vimatus, etc. 

 gjJi. triangulatus var., 31. revolutus, M. atavus, M. San- 

 der soni, etc. 



Monograptus cyphus, 31. revolutus, 31. atavus, 31. sandersoni, 

 Orthograptus mutabilts, Climacogr apt us tbrnguisti, CI. 

 hughesi, etc. 



Monograptus incommodus, Orthograptus mutabilis. 



Monograptus rheidolensis, 31. atavus, 

 Climacograptus tbrnguisti 

 (abundant). 



Monograptus atavus, Dimorphogruplus erectu 

 Climacograptus tbrnguisti. 



Climacograptus rectangularis. 



Orthograptus vesiculosus, Dimorphograptus 

 ef. extenuutus, Climacograptus medius. 



Cephalograptus (!) acuminatum, 

 Climacograptus medius, Sleto- 

 graptus mode?.tus, etc. 



Cephalograptus (?) acuminatus abundant, Jleso- 

 grapfus modeshis, Orthograptus cf. truncatus, 

 Climacograptus medius, etc. 



__ Climacogr. scalaris vars. normalis & miserabilis abun- 

 __i s dant, with illesogr. modest us & Gli/ptogr. persculptus. 

 ^Glypfograptus persculptus, and Mesograptus modest us 

 with var. purrulus abundant. 



[Scale : 1 inch = 150 feet.] 



