276 Geology of 



of this remarkable scarcity of animal life, but I need scarcely point 

 out of what value it is to the geologist now to be able to account for 

 facts which, before the deep sea dredgings lately undertaken, could only 

 hypothetically be explained. However, in one locality, there is ample 

 evidence that animal life was not missing, by the occurrence of 

 fossiliferous beds on the western side of Mount Potts, Upper 

 Rangitata, for it contains many brachiopods and a few gasteropods, of 

 which I have already given the principal genera on page 272. 



The lowest beds visible consist of shales often very carbonaceous ; 

 of micaceous gritty, generally tabular, sandstones, mostly of light 

 colours, some of them being full of fucoidal markings. The shales are 

 often slaty, and have a peculiar serpentinous look ; probably they 

 consist of ashes or are altered beds. Associated with them are 

 conglomerates, the matrix of which, mostly a quartzose ferruginous 

 sand, is sometimes so little binding that it is easily decomposed when 

 exposed to atmospheric action, but some of them are so hard that they 

 form buttresses standing prominently out from the mountain sides, 

 and then generally form the summits of the ranges. These conglo- 

 merates, like the succeeding beds, are often grouped in several horizons 

 separated from each other by thousands of feet. They are overlaid 

 by a series of compact diabases, diabasic tufas and cherts, with 

 occasionally beds of more or less altered limestones between them. 

 "Where these latter occur, they very often constitute the summits of 

 the ranges ; thus, to give only one instance, they form in the Malvern 

 Hills, the summits of the Flagpole Hill on the one side, and the Four 

 Peak range on the other ; while between them the saddle is an 

 anticlinal, consisting of loosely cemented conglomerates of the lower 

 beds. As before observed, the diabases of the Malvern Hills have a 

 compact structure, and I may here add that the more granular 

 varieties of the same rock occurring in the Nelson province, have 

 without doubt been erupted in the same geological period, and are of 

 a similar origin. 



It is very striking that these rocks have such a large extension in 

 our palaeozoic beds, both vertical and horizontal, and that in this 

 respect they closely resemble the diabases of the Hartz Mountains in 

 G-ermany, where they are also interstratified in beds of considerable 

 thickness, ranging from the lower devonian to the upper carboniferous 

 period. Professor E. Kayser, of Berlin, has given an excellent mono- 

 graph of these Hartz beds, in the Journal of the German Geological 



