Sedimentary Rocks. 57 



or Lower Ordovician, but in either case, the vertical distance 

 between the Upper and Lower fossiliferous rocks can only be 

 about 100 feet. 



The Dicellograptus shales outcrop downstream in the Glendoon 

 Creek for some distance, and are continued south in the bed of 

 the Djerriwarrh. A cliff on the right bank of the Djerriwarrh 

 yielded — 



Diplo graptus. 



Climacograp tus. 



G I osso graptus, 



Dicellograptus, cf. sextans, J. Hall. 



Crypto graptus tricornis, Carruthers. 



Nemagraptus gracilis, J. Hall. 



Retio graptus, cf. geinitzianus, J. Hall. 

 The next fossiliferous beds downstream yielded only a few 

 specimens of Didymo graptus caduceus after a long search, but 

 the vertical distance between these Lower Ordovician beds and 

 the Upper Ordovician cannot be greater than the interval be- 

 tween two zones of the Lower Ordovician at a typical locality 

 in a district like Castlemaine. A little further south, Lower 

 Castlemaine beds are found. The graptolites, etc., from these 

 have already been listed on page 47. We measured the distance 

 from these beds up a small tributary to Dicellograptus beds, and 

 found it to be about 100 yards. The same beds were also traced 

 north along the western bank of the creek, to a point not far 

 west of Upper Ordovician outcrops in the creek itself. This 

 was as far south as our detailed observations extended; but, 

 further south, Middle Bendigo graptolites were obtained from 

 the bed of a western tributary of the Djerriwarrh, and Tetra- 

 graptus fruticosus and Didymo graptus bifidus were obtained 

 from the Boggy Creek, west of Toolern Vale. 



(c) Summary. 



Nowhere was the actual junction between Upper and Lower 

 Ordovician detected. The two series are undoubtedly uncon- 

 formable, though the unconformity is not apparent in the field. 

 It is difficult to imagine that Lower Castlemaine beds in one 

 place, and Lower Darriwil, a little further north, are only a 

 few hundred feet, or less, below Dicellograptus shales, unless 

 they have been brought into that position by faulting, for there is 

 nothing to indicate any great difference in the conditions of 

 sedimentation at Gisborne, compared with those prevailing at 



