410 Transactions. — Miscellaneous. 



character of this deposit is unmistakable, as seen in the 

 "washed-out" gulhes so numerous all over the valley: the de- 

 posit is clearly stratified ; it is made up mainly of rounded 

 particles of pumice, interstratified with layers of clay and 

 rhyolite sands, and enclosing the trunks of trees placed 

 horizontally. That these deposits were brought down by the 

 Waikato Eiver seems unquestionable — pumice-drifts are not 

 found in the valleys of any other rivers which flow into the 

 Waikato middle basin ; but how they came to be laid as we 

 now find them is, in my opinion, the most interesting physio- 

 graphical question which we have to deal with. Reference to 

 the map (PL XXXIV.) will show the surface-height of the 

 land at Cambridge to be 220ft. above the sea ; at Hamilton it 

 is 120ft. ; at Ngaroto, 125ft. ; at Morrinsville, 82ft. ; and at 

 Taupiri only 39ft. Now, we find the alluvial deposits have 

 been carried by the Waikato waters to the Eotorangi swamps, 

 eight miles almost in a southerly direction from Cambridge, 

 wlailst the natural fall of the country is in the direction of 

 Taupiri, and over 7ft. to the mile. Dr. Hochstetter says of 

 the middle basin : "The geological features of the basin are 

 these : The lowest bed consists of layers of clay and sand, 

 with bituminous shale, which, in some places, encloses trunks 

 of trees changed to lignite ; the shale passes into argillaceous 

 shale, containing numerous fossil plants ; these and similar 

 strata point to the fact that the whole middle Waikato basin 

 was but recently a shallow bay of the sea, at the bottom and 

 on the margin of which these layers were formed." 



If this be so, as the land rose and the sea receded a 

 channel or channels would be left in the estuary, and 

 through these channels the rivers and streams of the valley 

 would naturally continue to flow into the Hauraki Gulf. 

 We find, however, the places where the old estuarine chan- 

 nels might have been are filled with the fluviatile deposits, 

 placed in such stratified form that they could only have been 

 laid down by the action of very slowly-moving water in a 

 lake or the sea. The depths of these deposits vary con- 

 siderably : in the Eukuhia Swamp, between Hamilton and 

 Ohaupo, they are from 50ft. to 70ft. ; in the Piako Swamp, 

 from 40ft. to 60ft. ; at Hamilton, from 40ft. to 70ft. ; and in 

 the neighbourhood of Taupiri, the lowest point in the basin, it 

 is a remarkable fact that the deposit is lightest. Beneath 

 these deposits in several parts of the valley the ancient land- 

 surface can be seen. In the Waikato Eiver, near Hamilton, 

 are standing several trunks of maire trees, which appear to be 

 standing as they grew. In several of the "washed-out" 

 gullies the same may be observed — the trunks of trees lying 

 horizontally and some standing erect on the old surface. 



The most interesting example of this character, because 



