Geolofiy of the Country dboiit Ant/ief^ea. 47 



The black, sandy clays Ijctwoeii liere and Point Addis are 

 Aveathered to a fawn colour in their upper part, and the chani^e 

 to purplish black is rather sudden. As the weathering follows 

 the contour of the ground, the beds appear to form a gently 

 swelling anticline, with the lower beds showing to a thickness 

 of about 40 or 50 feet in the middle of the section. An exami- 

 nation, however, shows that the appearance is deceptive, and 

 is merely a colour ett'ect. 



The chief peculiarity in the black series is its jointing. In 

 one place not far from Anglesea rectangular prisms, with a 

 four or live inch face, are developed, the joint faces being verti- 

 cal. In other places, and far more commonly, great sheets 

 flake off the vertical cliffs and fall or hang in threatening posi- 

 tions nearly a hundred feet above the beach. Still nearer to 

 Point Addis, for over half a mile, the cliffs, here about 150 feet 

 in height, form a confused mass of tuml^led heaps. The dip of 

 the undisturbed strata is small, but holds steadily to seaward 

 along the straight coastline, and great masses have apparently 

 glided down the dip-slope and formed the landslips. The di]) 

 can be seen along the shore towards Point Eoadknisht, and on 

 a small point a couple of miles west of Point Addis. 



The siliceous grits which were noted in the lower part of 

 the Addis Limestone also occur in the underlying series even 

 down to the lowest part of the black beds. They seem to grow 

 coarser near the top of the cliffs, and small beds of waterworn 

 <|uartz-gravel occur frequently here, near where the limestone 

 jirobably once lay before its removal by denudation. 



In the black, unweathered beds seams and small nodules of 

 iron pyrites are of comniion occurrence. The weathering of tliis 

 into copiapite was noted by Daintree, while near Point Jioad- 

 knight alum occurs as an incrustation which has a greenish 

 tinge. 



Remembering Daintree's record (if jiyritic casts from the i)eds 

 near Point Addis, I searched for a long time near Anglesea 

 for fossils in these barren beds. The occurrence of li<jnitio 

 fragments, which are fairly common in places, gave me the idea 

 that perhaps the beds were, after all, of freshwater origin, l)ut 

 later on this idea was dissipated by the finding of a tooth of 

 OdoiitdpiH contortidens Ag., and numerous examples of fora- 



