Bartrum. — Westport-Charleston High-level Terraces. 259 



of the Little Totara the uplifted stratum of moderately resistant limestone 

 seen in the cuesta early resisted the advance of the sea and protected the 

 weaker " Blue Bottom " sandstones overlying it to the east. 



The origin and mode of deposition of these gravels are of interest. The 

 basal members, which are said to contain " black-sand " gold-leads, are 

 beach deposits, and it is probable that a great portion of the gravels above 

 these were brought down by the Buller River and other streams, and dis- 

 tributed by wave-action along the shore-line. If it is assumed, as may 

 reasonably be done, that a moderately constant and abundant supply of 

 waste was maintained from the relatively uplifted inland district, it may 

 be concluded that the marine shelf was cut during a period of slight de- 

 pression, and that during ensuing standstill the progradation of the coast 

 was effected. Sufficient standstill occurred at this juncture to permit of 

 the widening of the bed of the Totara River at its debouchure from the 

 granite and gneiss mountains to a width of about 200 yards where now the 

 present stream flows in a narrow gorge 100 ft. below the lip of this rock 

 platform. The uppermost members of the gravel series were laid down 

 as fan deposits by the Buller River and mountain torrents from the up- 

 faulted Paparoa Mountains during the early stages of a succeeding move- 

 ment of elevation. 



(2.) Lower Terraces and Flats. 



The terraces and flats forming the extensive lower belt extending 

 seaward from the foot of the higher terraces, and attaining a width of over 

 seven miles between Cape Foulwind and Addison's, are essentially related 

 in origin to the high-level terraces. After the formation of the piedmont 

 plain noted above, elevation of at least 250 ft., ensued, and was followed 

 by a period of standstill, and perhaps of slight depression, causing the 

 re-advance of the sea until the former piedmont plains were cut back and 

 formed an elevated coastal fringe, notched by the Buller River and by the 

 torrential streams from the Paparoa Range, and with high cliffs marking 

 the line of sea-front. South of the Little Totara River the tilted limestone 

 stratum again proved a barrier to wave-advance. At the base of the sea- 

 cliffs highly auriferous beach-drift was deposited, constituting one of the 

 richest gold-leads of the district, and, prior to the re-elevation which now 

 followed, gravels 30 ft. and more in depth were laid as a covering upon the 

 beach-sands by the larger streams, such as the Okari and Totara Rivers, 

 which had time at this stage to widen their flood-plains enormously by 

 the undercutting of the " 500-foot " terraces. 



An interesting remnant of the former coastward extension of the high- 

 level terraces which has escaped complete destruction by the advancing 

 sea, and later by the lateral erosion of the Totara River, can be seen beside 

 the Charleston Road, about a mile and a half north-east of the Totara 

 River bridge. 



Several pauses during this latest movement of re-elevation are evidenced 

 by the numerous terraces so well seen on the west bank of the Buller. 

 Lines of auriferous beach sands and gravels were also left to mark periods 

 of more especial concentration of the gold present in the drift, which 

 was deposited in moderate abundance by the retreating sea, and have 

 proved of considerable economic value in many localities. The depth of 

 such old beach material is seldom more than about 12 ft. to 20 ft. ; with 

 it are often associated erratic boulders and blocks, sometimes 8 ft. and 

 more in diameter, which must owe their present position largely to glacial 

 transport. 



