low platform on the beach, it is difficult to be sure either of the direction or the angle of the dip. Fig. 3. Plan of Cheltenham Beach ash-beds: 1. Band of volcanic grit. 2. Sandstones and shales (shows here (2) as dome). AB. Low sandy flat called the “Narrow Neck.” 3. Outcrop of grit further north, only showing on beach. The two outcrops showing along the shore-line at CD and again at E are evidently portions of the same land as shown in above plan. This bed, dipping east at CD, has presumably had its dip changed by the same force which formed the dome, and appears again at E dipping west. The strata at the end of the point are truncated by a fault as shown. To the southern side of the point the dip rapidly increases until at the fault the strata become vertical. In a paper read before the Auckland Institute in 1889 Mr. Park gave a plan of the Cheltenham Beach ash-beds. In this, however, no notice is taken of the change in the direction of dip in the two exposures, nor is any mention made of the dome. Both of these matters have an important bearing on the question under discussion. Furthermore, the northern outcrop is obtained by producing the line CD (fig. 3), whereas in point of fact it occurs considerably to the west of this position. The outcrop at F (fig. 3) may have reached its present position owing to being horizontally displaced by a strike fault running east and west. The low swamp occurring between the higher cliffs on either side may well indicate some faulting of the strata, in consequence of which the sea has been able to effect an entrance and erode the narrow valley, now become a dry sandy flat. Additional force is lent to this theory by the fact that a line drawn across the narrow neck east and west would pass through low mud-flats and the waters of