DopsoN.— Notes on the Glacial Period. 295 
such as the wearing down of the mountains by glacial and other action, and 
the destruction of land by the sea—have all tended to render the climate less 
rigorous, the subsidence of the land has to be looked to as the chief cause of 
the termination of what may be called, for the sake of convenience, the glacial 
period. 
On the west coast of the Middle Island the effects of glacial action, as 
exhibited by masses of moraine matter covering large areas, are so striking as 
to arrest the attention of even the most superficial observer. Struck by the 
recent appearance of many of the moraines, and the manner in which glacial 
drift caps the general drift of the country, I have ventured to collect the 
numerous notes I have made during the last ten years, and from them deduce 
what I conceive to have been the changes which have taken place during the 
latest geological periods. 
At the end of the pliocene period I consider that but little of the 
Middle Island stood above water; the main back-bone of the island probably 
constituted a series of rocky islands, the sea level being about 2,000 feet 
higher during this period, which must have been of great duration; the 
gravel drifts were formed which cover the greater portion of the level lands, 
and cap all the older formations from Nelson to Hokitika, During this period 
were formed the Moutere Hills, and all that great face of drift hills which 
occupies the whole of the depression between the east and west ranges, from 
the southern shores of Blind Bay to Lake Rotoiti. Here the drift formation is 
interrupted by the mountains which divide the Lakes Rotoiti and Rotoroa, 
and also by the mountains forming the watershed between Rotoroa and the 
westward streams. Again, the drift formation occurs in the valleys of the 
Matakitaki and Maruia, and then continues on almost uninterruptedly, capping 
the older rocks throughout the flat country right down to the Mikonui River. 
Following the coast northwards from the Grey, the drift again occurs in all 
available places for deposition at heights varying from 10 to 500 feet above the 
present sea level The reason for the drift attaining such a much greater 
height at the head waters of the Buller and Grey was, that there the drift was 
free from the destructive effects of stormy seas, and was deposited by streams 
flowing into a quiet strait protected by high land on the east and west, and was 
subjected only to the settling action of marine currents running through the 
Strait; whereas on the coast line the heavy westerly swell from the Pacific, 
aided by the strong littoral currents, prevented the deposition of drift except 
in sheltered places. 
It was during this period that the formation of the great gravel drift 
of the Canterbury plains began. Тһе country there began to rise, and 
although the formation of gravel drifts continued on the lower levels, the 
waters of precipitation began to earve theu on tho higher levels into the forms 
