REPORTS OF RESEARCH COMMITTEES. 339 



P. Marshall* has explained the more important features of the 

 present surface in the Tuapeka district, Otago, as due to " move- 

 ments cf tilting from south to' north," associated with a certain, 

 amount of local faulting, " and of thrust from south-east to north- 

 west," deforming a peneplain developed subseqviently to elevation, 

 accompanied by a considerable amount of faulting, in the late 

 Tertiary. 



With the object of making an estimate of the i-ate of erosion by 

 glacial sccur Marshallf has also made a number of observations 

 o'i the amount of sediment suspended in the water of the Hooker 

 River, flowing from the Hooker and Mueller glaciers, finding the 

 average to be 1 part of sediment in 15,523 parts of water. 



E. S. Mocre;]; has given a general account cf the distribution of 

 the volcanoes of the North Island and discussed their relation to 

 structural lines. He notes an absence of evidence of glaciation in 

 the volcanic zone. 



P. G. Morgain§ has noted tnat the Paparoa Range (west coast 

 of South Island) is a tectonic block, partly ant clinal and in part 

 bounded by faults, while the neighbouring broad valley of the- Grey 

 River is mainly a tectonic depression. The lower country border- 

 ing the west coast he describes as a dissected coastal plain, and he 

 notes that extensive progradation of the shore-line is now in pro- 

 gress. , 



In collaboration with J. A. Bartrum, Mci'gan has recognised 

 tectonic blocks, large and small, forming large topographic features 

 and determining river courses in the Westport district, while some 

 rivers now in deep gorges are found to be antecedent. Plateau 

 surfaces are found to be due to stripping of weak strata in some 

 cases from the resistant ''coal-measures grits and sandstones" 

 (Tertiary), and in other cases from the floor on which the Ter- 

 tiary formations were deposited. To the latter the term " fossil 

 peneplain " is applied, and it is suggested that this is the origin 

 of the flat-topped highlands of Nelson, Westland, and Canter- 

 bury, described previously by various authors as remnants of a 

 peneplain. The present land-surface is said to bear in many 

 places ' ' a close relation to that existing immediately prior to the 

 Eocene, "li 



• p. Marshall, Tuapeka District, N.Z. Geol. Survey Bull. No. 19 (new series), 191S. 

 t P. Marshall, Note on the Rate of Erosion of the Hooker and Mueller Glaciers, Trans. \N.Z. 

 /ns«. .vol. 45, pp. 342-43, 191.3. 



1917 ^^' ^' ^^'^°'^^' ^'^^ Active Volcanoes of New Zealand, Journal of Geology, vol. 25, pp. 693-714, 



§ P. G. Morgan, Greymouth Subdivision, X.Z. Geol. Surv. Bull. No. 13 (new series), 1911. 

 II P. G. Morgan, and J. A. Bartrum, BuHer-Mokihinui Subdivision, X.Z. Geol. Surv. Bull. No. 

 17 (new series), 1915. 



1084—20 



