STRUCTURAL FEATURES COMMITTEE. 237 



this Bulletin, but it is stated that any description of it would involve 

 the consideration of the structure of the Alpine Range. Various faults 

 traversing the coal measures are also maintained and described, but 

 they are probably of no great tectonic importance. 



Bulletin 12 deals with the Dun Mountain Region. This district is 

 of great importance, since Hector largely constructed the fabric of New 

 Zealand Geology on the structures he found here. McKay and Hector 

 had stated that the Triassic, Permian, and Carboniferous rocks of New 

 Zealand were in this district separated from one another by thriist 

 planes. The writers of this Bulletin, Bell, Marshall, and Clarke, have 

 arrived at very different conclusions. No structures were found in 

 any way suggestive of reversed faults, but the rocks were seen to be 

 intensely folded, though the folding had not been associated with any 

 metamorphic action. No fossils were found that suggested that more 

 than one series of rocks was present, and that series is referred to the 

 Trias -Jura. 



Throughout New Zealand a longer mass of rocks, especially those 

 of the main mountain ranges, has been classed as Carboniferous, on 

 the basis of the statements that were made about the structures 

 described in the Melsan district. The authors of the present Bulletin 

 have altogether failed to find any Carboniferous rocks in this typical 

 district, and it thus appears that the whole mass of Maitai rocks 

 hitherto classed as Carboniferous must now be placed in the Trias-Jura 

 formation. 



The great ultra-basic igneous mass of the Dun Mountain was found 

 to be intrusive into the Trias-Jura rocks. It is suggested that the mass 

 was intruded after these rocks had been folded. The ultra-basic 

 mass is therefore of post Jurassic age. 



Bulletin 14 deals with the oil-bearing district of Taranaki. Clarke 

 the author, finds two rock series only. One of these is of Tertiary age, 

 and is nearly horizontal over the whole area. The other is purely 

 volcanic in origin. 



Three tex- -bool:^. on ihe Geology of New Zealand have appeared 

 lately. That by Park hugely follows, so far as the older rocks are 

 concerned, the hand-book by Hector, except that the schists, both 

 crystalline and foliated, are referred to the Ct.rnbji. i;. rrd much 

 importance is ascribed to faults in the structure of the country. 

 Marshall, in his two works, classes the gneissic schists as Archaean, and 

 the foliated schists as metamorphic sediments, probably of Trias-Jura 

 age. He suggests that the Alps are formed of a series of isoclinal folds, 

 and considers that the structures are not yet sufiiciently well-known to 

 justify state jnents as to the importance of faults. In these works of 

 Marshall, all the younger rocks, fronijj^per Cretaceous to Upper 

 Miocene, are regarded as a single confo^^l)le series, d^jQgited during a 

 period of progressive subsidence. 



