364 The American Naturalist. . [May, 



that these Moas died thousand of years ago, long before there 

 were any human inhabitants to light fires, it will be seen that 

 tli is surmise is quite out of the question. Only two hypotheses 

 appear to be possible to account for the facts. Either the birds 

 walked into the swamp and were drowned or else their dead 

 bodies were washed in. The first hypotheses is probably the 

 explanation of the deposit at Te Aute near Napier, because 

 many of the leg bones were found upright in their natural 

 position. But at Glenmark and at Hamilton the bones were 

 lying in all directions, as often upside down as in any other 

 position, and the peat-beds were only a few feet thick, and 

 filled with bones up to the very top. We cannot, therefore, 

 suppose that these Moas were swamped, and there is evidence 

 in both of these cases to show that the dead bodies of birds 

 were washed in by floods. We find corroborative evidence of 

 this in the alluvial plains of Central Otago, for these always 

 contain numerous bones wherever a stream enters them from 

 the hills. 



But how are we to account for the number of dead birds 

 washed down from the hills ? There are two remarkable facts 

 connected with these bone deposits at Hamilton and Glen- 

 mark. One is the very large proportion of bones of young 

 birds from one-half to three-quarters grown ; and the other is 

 the absence of Moa egg shells. These two facts seem to show that 

 the birds perished in the autumn or winter, when the birds of 

 the year were not full grown, and when the females did not 

 contain any hardened eggs. Also, it is evident that dead 

 Moas could not be washed into swamps under the present en- 

 matic conditions, and the explanations of the puzzle must He 

 in the fact that in pleistocene times, when these bone deposits 

 were formed, the climate was very different from what it is 

 now. At that time the eccentricity of the earth's orbit was 

 very great, and when winter in the Southern Hemisphere hap- 

 pened in aphelion, long cold winters were followed by short 

 and very hot summers. It seems probable therefore, that the 

 early winter snows killed hir-v numbers of Moas and other 

 birds on the hills, that their bodies were floated down by 

 summer floods and avalanches caused by the melting snow, 



