TIIK OKDOVICIAN SVSTKM 



I I :; 



Fig. -'(>. GROUP OK AltKNKi AND I.LANDII.O KO881LS. 



a. Didymograpttis Murchisoni. 

 l>. Acidaspis Jamesi (Irish). 

 '. Orthis al.itu (Arenig).' 



('. Trinueletis Iiiabri;itu>. 

 e. Asaphus tyrannus. 

 J. Ogygia Buc-hi. 



Fig. 27. UEOUP OF LLANDlI.c AM' MM. A CRAPTOLITE8. 



;n-o^raptU8 Iiicoini.s. 

 J. Diccllograptus si-xtuns. 

 3. Dicello-.Taptus zic/ac. 



4. Olo^.si.-!ai>tus Him-k.si. 

 .". Dicr.'iMo^niptiiH ramoxii.i. 

 G. Diplox'taptus foliaceiiN. 



