290 Mr. Brockbank and Mr. C. E. de Range on 



group. It commences with a very rough limestone, 4 inches 

 thick. When polished it has a pinkish brown colour, mottled 

 over with bright spots, which prove to be Spirorbis shells 

 cut through in every direction. The number of individuals,, 

 roughly counted, amount to 300 to the square inch, which 

 would give about 5,000 to the cubic inch. The limestone 

 is, in fact, almost made up of this tiny annelid. The second 

 limestone of this group is 10^ to 14 inches thick, with a 

 very irregular surface, the hollows filled in with green shale. 

 It has a deep purple fracture, and shews nearly as great an 

 abundance of Spirorbis when polished. In addition, it is 

 mottled with oval and circular greenish spots ; under the 

 microscope these are shewn to be produced by Entoinos- 

 traca — beautiful oval shell sections are everywhere present.. 

 The third limestone of No. 2 group is 8^ inches thick,, 

 and has the same appearance ; when polished it has a 

 beautiful dark marble lustre, much mottled with dark and 

 light oval patches. The dark mottlings have a granulated 

 substance, and are probably coprolitic. It is also dotted 

 over with an immense number of Spirorbis shells. A 

 microscopic cutting taken from another block shews the 

 marble to be completely made up of small organisms and 

 beautiful oval shells of Ostracoda^ cut through at varying 

 angles, some showing the overlapping of the bi-valve 

 shells. The delicate shells are so completely absorbed into- 

 the substance of the limestone that it is impossible to detect 

 their presence except by the green mottling which they 

 produce, and which is very noticeable. There are also 

 present many minute filiform objects, probably ^er- 

 pidites and other annelids — many tiny bones are also 

 visible. The 4th limestone of No. 2 group is i foot 

 I inch thick, and a thin parting of brown shale sepa- 

 rates it from the 5th limestone, which is i foot 5 inches 

 thick. They are frequently conjoined, forming huge blocks,, 

 so they may be here taken together. They have the same 



