WHERE WAIKATO ONCE FLOWED,

Auckland Star, Volume LIX, Issue 123, 26 May 1928, Page 8

WHERE WAIKATO ONCE FLOWED,

The other day. motoring through the Hinuera Valley on the main road from Cambridge to Matamata, one could not help but be struck by the wonderful geological story which that bit of the Waikato countryside had to tell. Hinuera correctly it is Hkm-wera, meaning "'Hot Oil") is the place where Dr. P. Marshall, geologist to the Highways Board, recently discovered a great quantity of vitreous rock exceedingly useful for road making. Those rock columns and bluffs form the vertical walls of the Hinuera Valley for many miles. We drove along a smooth, almost level road from the terrace above the Waikato banks a few miles above Cambridge until we approached the Rotorua railway line. It was impossible to mistake tile history of land and water as revealed for us in the peculiar contour of that eastwardtrending valley and its cliffy wall. Anciently the Waikato River flowed through this level-floored valley into the Upper Thames. \ alley and northward into the Firth of Thames. Most likely, indeed, the Firth of Thames, as we know it on the map, did not exist in that geological age: the sea flowed, probably, as far inland as where Morrinsville is now. The Waikato, after flowing through its winding gorges as far as Horahora, found its course obstructed by the rocky hills at the base of the Maungatautari Range, turned eastward''along this valley formed by volcanic action and so across the Matamata Piain, where the Waihou joined currents with it. The Hinuera Valley is higher than the present bed of the Waikato, but comparatively slight tilting of the land is sufficient to account for alterations in course, and the successive terraces along the Waikato banks speak eloquently of the days when the waters flowed at a higher level. This is but one of the chapters in the long and varied story of our river. It is probable that the Waikato originally flowed from Lake Taupo northward to the Bay of Plenty. Slow changes in land level or quick changes due to volcanic agencies and earthquakes, and also the excavating powers of-water in volcanic deposit would account for the diversions of course through the pumice' country. The second stage in Waikato's career saw it flowing through the Hinuera Valley. At a later period the western ranges, where Xsraruawahia is now, deflected it eastward to the Piako and the Hauraki. The Mangawhara Creek, at Taupiri, indicates to-day its'ancient course before some convulsion of the earth opened for it a nirhe through which it might gradually force its way dne northward and so on to its ultimate destination, the Tasman Sea.

That Hinuera Valley, with its gorge-like character in places, its' bold, dark, vertical"bluffs of columnar rocks, cave-riddled,, should be a fascinating place for the student of geology is certain. It is one of the most accessible* of Nature's classrooms for those who would learn to read the story of our little corner of the earth. —J.C.