■S30 Tra usactions. — Geology. 



further eastward than it does at present. We may then see 

 in this well-drained north-eastern angle of the dolerite and 

 loess plateau the mustering and alighting-ground of swarms of 

 birds migrating to and from less frigid regions with each re- 

 curring year. I cannot see how the partial distribution is to 

 be otherwise accounted for. But there is another difficulty. 

 Sea-birds do not use gizzard-stones, their use is confined to 

 granivorous birds, and these seldom or never discharge them. 

 Are these multitudes of stones, then, a mortuary talus? If so, 

 why their markedly greater number near the coast ? I have 

 never met with any statement on the subject, but I think it 

 more than probable that birds about to take a long migratory 

 flight will unburden themselves as much as possible before 

 starting, including the discharge of their gizzard-stones. It 

 is worthy of note that bird-stones are numerous in some 

 places in the clefts in the dolerite, deposited there before the 

 loess began to fall ; and also that the loess in the upper por- 

 tion, including the compressed and pugged layer and a few 

 feet beneath it, is barren of them. From the last fact it is to 

 be inferred, if the general explanation is correct, that the 

 climate became too severe to allow the birds to visit this 

 region. 



In this connection must be mentioned that in the lo^/est 

 layer of the deposit stones are to be found which could only 

 have been used by large birds of the moa family. I have 

 found an odd one or two higher up, and also fragments of 

 bones ; but in the lowest layer I have seen two nests, so to 

 speak, of large stones. In my last paper on the red gravels, 

 it was stated that bones of large birds have been found be- 

 neath the dolerite ; therefore there is nothing to be wondered 

 at in finding relics of such birds in the later formation. There 

 is this curious fact, however, in connection with the majority 

 of the pebbles in one of the nests referred to : that they were 

 unquestiona^bly picked up by the bird or birds from an exposed 

 sea-beach. They are of the same or very similar rock material 

 as those forming the bulk of the present sea-beach, i.e., 

 Waitaki shingle, and they have the discoid shape produced by 

 the action of the waves on the beach. I have been very care- 

 ful to make sure that these pebbles are really imbedded in the 

 original deposit, and not merely surf- washed and mingled with 

 shp stuff, cases of which can be seen all along the cliffs. A 

 VcXgue and unsatisfactory inference might be suggested from the 

 fact stated, that the beach from which the pebbles were ob- 

 tained was not far away, and, from this, the further inference 

 that the land in that case could not have been at a much 

 greater elevation than at present. In the second nest referred 

 to, the pebbles were all well-rounded. 



Before leaving the loess, I would suggest that the upward 



