Tuomson.—Glacial Action in Otago. 325 
and which, also, have numerous rivulets running into and joining them, we 
will have the examples required. "Then observe the banks of the lake or river 
at full flood, and you will see no indications of terraces, unless under water. 
Above the flood-line, no doubt, will be seen the terraces of former ages, but 
within the limits of rise and fall of the lake or river itself is only to be seen 
the action, in miniature, which is of use in illustration. Then it is by receding 
waters, or waters that have receded, that the terraces became apparent—of a 
river or lake in a few months ; of the great ocean in many centuries. Yet the 
action and results are precisely similar; for, looking at the conformation of the 
surface of the shores of a lake or river where the feeder, or rivulet, enters, you 
will see the slopes divided into terraces: highest near the flood marks, lowest 
near the low water; most inclined near the flood mark, least inclined near the 
low water; the largest particles or pebbles near the flood mark, mere sand or 
mud near the low water; thus conforming, in every respect, to the gigantic 
formations which we are now considering. And let two streams enter a lake 
or river closely adjoining—the spurs between will be the same—sloping with 
the opposite terraces, and the talus will reach out in the manner that the 
receding waters had tended. If this be the law in small areas, so it is in great. 
It is, therefore (after glacial action had filled up the valleys with débris), to 
the receding waters of the ocean, assisted by influx and reflux of tide, with the 
feeder from the mountains at the head, that we may, without fear of 
contradiction, ascribe the hollowing out of the gullies in the terraces, and the 
transport of the smaller gravel and sands towards the ocean shores, Thus, 
while the glaciers brought down the shingle and deposited it all over the valleys, 
the succeding action of scoring out the terraces themselves into gullies was 
effected by the land rising, or, in other words, the ocean receding. 
And while we see the terrace formations most prominent in the interior, 
most inferior near the coast, this is also due to the interior ones having been 
protected from the ocean surf by the enclosing mountains, while those on the 
seaboard have been subject to the full force of this degrading power. The 
whole formation of terraces, as we now see them in Otago, therefore, we may 
reiterate, have been the result of the mechanical action of nature operating, 
first in the long period of the glacial age, then afterwards by the rise of land, 
in which the tides of a receding ocean and the fresh waters of the mountains 
together acted as moulders of the present forms in their bold fronts, long 
reaches, abrupt rises, deep indentations, and mathematically-curving slopes. 
With the well-known fact before us, that gold is found disseminated in 
quartz veins, and reefs intersecting the schist rocks, of which the mountains of 
the interior are principally composed—a fact so intimately connected with one 
of the most important industrial pursuits—some allusion to it is called for. The 
allusion must necessarily be a mere passing one, as no justice can be done it 
