Speight. — The Intermontane Basins of Canterbury. 339 



• 



of the pre-Cretaceous sea, invading even the narrow tortuous fiords that 

 stretched far back among the mountains of that date, as, for example, into 

 the Trelissick basin and along the ancient rift-like Clarence Valley." 



Again, on page 98, he says, " The marginal distribution of the rocks of 

 the Karamea system ; the manner in which they ramify into and around 

 the narrow fiord-like valleys in Nelson and Otago ; and the mantling sheet 

 thev form in western Nelson, gradually ascending from sea-level up to 

 4,000 ft. on the higher slopes of the main divide, seem to afford indubitable 

 evidence that the main tectonic features of the country were already deter- 

 mined before the advent of the Cainozoic epoch." However, when referring 

 to the folded limestones at Bob"s Cove, Lake Wakatipu, he says (page 100), 

 " Here we have a portion of a marine littoral involved in a great crust fold, 

 and elevated to a height exceeding 5,000 ft. above the sea, affording clearest 

 proof that a sea-floor existed in the early Miocene where the Richardson 

 Mountains now stand." 



Later, on page 144, he points out that marine conditions extended over 

 a great portion of Central Otago, and that the block mountains were formed 

 not by the subsidence of the portions of an elevated plateau, but by the 

 uplift of the adjacent strips of territory. 



It is apparent from these statements that Park certainly regarded Central 

 Otago as a sea-bottom in Tertiary times, and that the marine deposits of 

 Canterbury were laid down in arms of the sea, and were not the remnants 

 of a widely extended overlying sheet. 



McKay, in his report of the Trelissick basin (Geological Reports for 

 1879-80, p. 59) regards this basin as the result of movements accompanying 

 the elevation of the surrounding mountains. Elsewhere in his reports 

 McKay appears to consider that the Tertiary sequence of beds was more 

 widely distributed, and that the remnants occurring in other places, such 

 as in the Clarence Valley, were due to strips being preserved owing to their 

 being let down along the lines of fault to levels where they were less 

 exposed to eroding agents. 



In connection with this, Hector states in his progress report for the 

 years 1888-89, p. liv, " The evidence collected is, it must be admitted, 

 strongly corroborative of the theory that the Cretaceo-tertiary and Arnuri 

 rocks once spread over the whole district, from the mountains on the north- 

 west side of the Awatere Valley to the eastern seaboard, and have only 

 disappeared from the higher elevations of the two intervening mountain 

 ranges on account of the intense denudation that must have taken place, 

 and is still taking place." 



And in connection with the Trelissick basin, Hector remarks (Progress 

 Report, 1885) that " the presence of fault lines in other parts of New Zealand 

 is shown by structural movements that have isolated areas of Cretaceo- 

 tertiary and Upper Tertiary strata, such, for instance, as the Trelissick 

 area, which has been erroneously described as a basin." 



Marshall gives no definite pronouncement as to the origin of these 

 basins, but in his " Regional Geology," page 41, he insists on the presence 

 of land of considerable extent, bold coast-fine, and small rivers, while the 

 glauconitic members of the middle of the Tertiary series were being laid 

 down, with the sea in the area of deposition of approximately 200-300 

 fathoms deep. He notes, too, the extreme variability of the character 

 of the deposits, the great thickness of conglomerate on the west coast of 

 the island, the remarkable changes in the thickness of such beds as the 

 Grey Marls, but concludes that the land-surface was depressed after long- 



