Crawrorp.—On Fossils in Paleozoic and Triassic Rocks. 568 
very little solid rock within the whole area that can be used for building 
purposes, because the rock is so much jointed that it readily breaks into 
angular fragments. 
Now what does this extreme irregularity indicate? I should say 
deposition in a sea agitated by rapid, conflicting, and changing currents. 
This would indicate a state of things unfavourable to the growth of animal 
life; and destructive, during the process of deposition, to such life as might 
exist. ^ 
It seems to me that this is the most probable theory to account for the 
remarkable absence of fossils in the upper paleozoic rocks of this country. 
I only throw out this theory, howeyer, in a tentative manner. I can see 
that, in certain localities where the tides and currents are rapid, conflicting 
and changing deposits are no doubt going on, well filled with the remains of 
organic life. Thus in the British Channel, and the great fishing-grounds 
of the North Sea, there are no doubt great quantities of the shells of 
molluses, and of the bones and teeth of fishes, deposited with the detritus 
brought down by rivers, or re-arranged by the changing currents. There- 
fore there may have been other causes at work than those above indicated. 
The depth at which the deposition took place may have to be taken into 
account, as also possible changes in the direction of currents. We may 
suppose that if, from changes in the sea-bottom, an equatorial current were 
diverted into one from the poles, or vice versa, from a polar to an equatorial 
current, a complete destruction of animal life within the area might take 
place, and a long time might elapse before new forms of life spread from 
the nearest parts then presenting a similar temperature. 
I would by no means, however, discourage attempts to find fossils 
within the area of the newer paleozoic rocks. When we consider for how 
long a period the slates, sandstones, and limestones of the older palwozoic 
rocks of Wales were considered to be azoic, but were afterwards found, by 
Sir Roderick Murchison and others, to be rich in fossils, we need not 
despair, for a long time to come, of finding fossils in the ranges of Tararua, 
Ruahine, etc. Whoever shall make this discovery will have reason to 
congratulate himself on having added another link to the chain of New 
Zealand Geology. 
When I speak of these rocks as upper palæozoic, I refer to their relative 
position to the schists of the older silurian rocks of Otago, and other parts 
of the Middle Island, and therefore conclude that they are probably upper 
silurian. The term of upper paleozoic might otherwise be held to mean 
carboniferous or devonian rocks. 
Against this idea, however, it may be stated that the composition of the 
sandstones and slates more resembles that of carboniferous, or devonian, 
