OLD NEW ZEALAND.

Timaru Herald, Volume XIIC, Issue 13980, 16 August 1909, Page 6

OLD NEW ZEALAND.

A FRAGMENT RESURRECTED. The excavation for tho southern septic tank, part of Messrs Hunt and Worry's drainage contract, has revealed a curiosity, of a kind, in the nature of the material cut into. The site of the tank occupies a part of the old Park Gully Creek, which has been merely a stagnant pool at this spot since the construction of a concrete invert to carry the storm waters. The excavation also included the prehistoric channel of the creek. How wide this was originally cannot be told, for while the tank pit cuts into the solid clay on the eastern side it does not do so on the western, except below the bottom of tho original creek. On the western side the excavation shows an upper layer, 5J ft or Gft thick, of soapy chocolatecoloured mud, which dries to a lighter colour, as of clay adulterated with cocoa. This suggests deposit, in a stagnant pool, of storm waters muddy with vegetable matter as well as with fine clay. The bed is remarkably even in texture, irom the bottom to near the top; but beneath it, in the lowest part or original creek bed, there is a thin layer of small wood, of sorts; manuka and ribbon wood, identifiable, white pine less certainly. At the very bottom also, there is a little heach sand and shingle; but none at all higher up among the chocolate-coloured mud. This is odd. Jf the sea could wash beach material so lar up the creek, at one time, why could it not do so a little Jatcr, and later still? If the present excavation were left unprotected, it would probably soon be filled with shingle. For the explanation we must go back to the time when the coastline hereabouts subsided, as it did, by 25 or 3U feet at least, as the Harbour lioard dredgiugs have proved Seeing how the reefs lie to-day, i J atiti reef prior to the submergence doubtless bore a continuance of ttie Patiti clay ridge, and the spot where the septic tank excavation has been made was. immediately after the subsidence, further inland than it now is. . The now beach formed .along tho new coast would commence as a weak or thin one, and a sea would be able to sweep some of it a long way up the gullies. Soon, however, a strong beach would be piled up, and it is quite evident that this did happen, as there is sliingle only at the bottom of the mud bed. The subsidence would allow the sea to cut away the clay upon the Patiti reef; there was probably, at the time of the subsidence, a big bank of shingle to the south of it> as there is to-day, and much of this would be set free to travel northwards, to build up onthelcesideof the Point a beach that the biggest seas could not overlap Some erosion has probably taken place since the date of "the subsidence, but the steep faces of the clay bank between the Otipua lagoon and Mill, street may'be chiefly due to the action of the before the heach was formed along the new coastline. 'i'lv miscellaneous sticks met witli in xhe original creek bed drift from the sea, which is most likely, or drift down tlis creek —puts the date of the siihsidenee of the land during the timiwhen South Canterbury was a bush-clad country. This is the testimony also of the' submerged forest of hig timber trees on the coast of northern Seadown, and of the scrub-clad country along the AViislidykc.