entirely. The new shore-line produced by elevation will soon be modified. In some localities it will be cut back by the waves, in others it will be prograded, and between the points of maximum sea-advance and maximum sea-retreat will be innumerable gradations. The under-water slope of a prograded shore is likely to be continued above sea-level by slope, fan, or deltaic deposits with little or no change of grade. After elevation, unless there is considerable difference in the nature of the terrestrial and marine deposits, the old strand-line will probably soon be obliterated. The summit and basal edges of sea-cliffs cut by the waves during a period of comparative rest are much more decided lines of demarcation. The summit edges, except on coasts where the controlling conditions are far more uniform than in New Zealand, are not likely to be horizontal even if the uplift is horizontal. The base of an old sea-cliff—that is, the inner edge of a coastal terrace—will probably furnish much more reliable information as to the nature and amount of movement of the strand-line; but, as explained by Darwin in the second chapter of his Geological Observation on South America, it by no means follows that the inner edge of a coastal bench on a horizontally uplifted shore is horizontal. “With respect to the basal or lower edges of the escarpments, from picturing in one's mind ancient bays entirely surrounded at successive periods by cliff-formed shores, one's first impression is that they at least necessarily must be horizontal, if the elevation has been horizontal. But here is a fallacy: for after the sea has, during a cessation of the elevation, worn cliffs all round the shores of a bay, when the movement recommences, and especially if it recommences slowly, it might well happen that, at the exposed mouth of the bay, the waves might continue for some time wearing into the land, whilst in the protected and upper parts successive beach-lines might be accumulating in a sloping surface or terrace at the foot of the cliffs which had been lately reached: hence, supposing the whole line of escarpment to be finally uplifted above the reach of the sea, its basal line or foot near the mouth will run at a lower level than in the upper or protected parts of the bay; consequently this basal line will not be horizontal.” This explanation has evidently a wider application than Darwin gave it. The base of any sea-cliff that, during gradual horizontal uplift, is unequally cut back by the waves, either by reason of unequal hardness of the rock or unequal protection from wave-attack afforded by promontories or coastal drift, will not be horizontal. And the New Zealand coast is formed of rocks so differing in hardness within short distances, and is so irregular in outline, that caution is necessary in interpreting the evidence afforded by the inner edge of a coastal terrace. Moreover, the base of a sea-cliff after uplift is peculiarly liable to be obscured by talus, alluvial, and dune deposits. Notwithstanding these defects the inner edges of raised shore-platforms furnish the most reliable information regarding land-uplift, and, provided observations are sufficiently widespread to eliminate local peculiarities, the evidence may be confidently accepted. Darwin in the work already quoted discussed the nature of the uplift between the periods of comparative rest or slight depression when the sea-cliffs were formed. He concluded from the uniformity in size of the pebbles over the whole surface of platforms miles in width, and from the fact that the shells strewing the benches were all of littoral species, that the uplift had been by small sudden starts such as those accompanying recent earthquakes, or, more probably, by such starts conjointly with a gradual upward movement, and had not been due to great and sudden upheavals. In New Zealand the irregular coast-line causes the beach deposits to vary greatly