416 Transactions.— Geology. 
but it is easy to suppose the eastern part to have filled up with a deposit of 
sand, to have become dry ground and supported vegetation, which after- 
wards gave way to the effects of wind or fires during a dry season, when 
the water again took possession, the sand being driven to leeward to form 
sand-hills. The Wairarapa or the Canterbury Plains offer peculiar ad- 
vantages for the formation of wind-formed lakes when the condition of a 
sandy soil is present. The north-west wind descending obliquely from 
mountains, with accelerated force through certain gullies, has a swooping 
action, which of course cannot affect the gravels and clays, but if it meets 
with sand can soon make a hollow for the reception of water. If this 
hollow should be in a position to be filled by storm-water, springs, or 
neighbouring streams, it becomes a lake, or possibly a swamp. 
The nature of the surrounding soil must also be such that the access of 
water to the hollow shall not be able to cut a channel of egress for it, 
otherwise the lake will be drained from natural causes. 
I place Burnham Water as a typical example of a wind-formed lake, and 
there is also a small lake below my house, which I have called the Miramar 
Lagoon, which had every appearance of being a permanent lake when the 
settlers arrived in the district. Since that time, from the destruction of the 
flax and other vegetation which surrounded it, it has undergone many 
changes, and is now generally dry in summer time. 
There is another mode of wind-formation of small lakes which I have 
observed, viz., by sand blowing across the mouth of a gully and damming 
back the water. This sort of lake gradually fills up with sediment, and 
eventually becomes a swamp, and, later on, dry ground. There are several 
examples of this sort of lake on the peninsula of Hataitai, in the different 
processes of lake, swamp, and dry ground. 
Art. LXVIII.—On Bidwill’s Front Hills. By J. C. Crawrorp, F.G.S. 
[Read before the Wellington Philosophical Society, 10th January, 1880.] 
Taere is a low range of hills, about seven or eight miles in length by about 
one mile in breadth, down which the road runs from the Featherston and 
Waihenga Ferry road to Mr. Bidwill's house, which forms an interesting 
meter of the immense work which the action of rain and rivers has per- 
formed in the Wairarapa Valley. 
. This range separates the low part of the valley to the westward towards 
Featherston, from the equally low part on the east containing the river flats 
of the Ruamahunga and the Wharekaka Plains. The height of these low 
