412 Transactions.—-Geology. 
railway station also showed that the silt was stratified, but this section is 
now obliterated by weathering, and I have thought it important to éall the 
attention of geologists to the section behind the dock while it is still fresh ; 
for no doubt it will soon become obliterated like the one behind the railway 
station. 
The origin of this silt deposit is of considerable interest, as it is im- 
portant evidence in discussing the question of the latest oscillations of level 
in New Zealand. Dr. von Haast, in his Report on the Geology of Canter- 
bury and Westland (1879), p. 367, calls it ** The Loéss Formation,” com- 
pares it with the loéss deposits of China described by Baron von Richthofen, 
and says that ‘‘ the general character and position of the principal loéss (or 
loam) beds in this province prove clearly that they have been formed by the 
modus operandi pointed out by Von Richthofen.” There is, however, one 
difference which he mentions, ** and that is the absence in the Canterbury 
beds of the peeuliar small marly nodules so common on the Rhine, the 
Danube, and in China." 
The modus operandi in question is the following: The fine particles of 
earth carried down the slopes by the rain are partly retained by the grass 
growing on the slopes, and the dust blown across the land by the wind is 
also retained by the grass, the roots of which also decay and assist in raising 
the ground ;—so that the formation is a mass of grass covered with fine 
earth and sand brought by the wind and the rain, and has, of course, an 
entirely subaérial origin. It is characterized by being unstratified, and by 
having a “ peculiar vertical capillary texture," caused by the decay of the 
roots of the grass. 
I am afraid that the well-marked stratification of the base of the Lyttel- 
ton silt deposit can hardly be reconciled with this method of formation, 
and there are several other difficulties which cannot, I think, be explained 
on the theory of a sub-aérial origin. 
In the first place the deposit is widely distributed x rests upon beds 
of very different mineral composition. According to Dr. von Haast it is 
found at the foot of Mount Grey and on the Moeraki Downs, where it lies 
upon tertiary argillaceous and caleareous sandstones; at the Malvern Hills, 
where it rests upon secondary sandstones and slates. At the southern end 
of the Canterbury Plains it occurs from the Orari to Timaru, where it is 
found on tertiary sedimentary and volcanic rocks ; and in some places it 
lies on the shingle of the Canterbury Plains. South of Timaru it can be 
traced beyond the Waihao, and in the valley of the Waitaki south of 
Elephant Hill. From my own observations I know that it is largely 
developed at Oamaru, where the base is also stratified, and that it extends 
as far south as Moeraki Peninsula. It is difficult to understand how so 
