Paek. — On Granitic Boclcs in the King-country. 357 



in a rounded spur which terminates abruptly at the stream. 

 Beyond this point the granite boulders become fewer, being 

 rapidly replaced by those of the argillaceous sandstone, and in 

 a short distance they disappear altogether. 



The section for the next few chains is somewhat obscured 

 by the trachytes which descend from the higher part of the 

 range at this point ; but a little higher up, at the falls, the 

 argillaceous sandstones are seen in situ, being well exposed in 

 the bed of the stream for a distance of 4 or 5 chains. 



At the falls the sandstones alternate with thin beds of hard 

 crumbling clays or mud-stones, and often exhibit a tendency 

 to weather in rounded concretions consisting of thin radiating 

 concentric layers enclosiug a hard nucleus. At a place about 

 4 chains above the falls they contain a thin irregular streak 

 of fine bituminous coal, and I noticed that here the sandstones 

 themselves were finely micaceous. They strike N.-S. (mag- 

 netic), and dip west at an angle of 45deg. Higher up the valley 

 the coal-measures wrap over the outcrop of the older sand- 

 stones and close the section in that direction. 



[A sketch was here included, showing the position and 

 probable relation of the rocks met with in the line of section 

 just described, extending from the mouth of the Mangaone to 

 the falls.] 



Eeturning to the conglomerate, a close examination showed 

 that the fragments of granite and sandstone were mostly well 

 water-worn, rounded or subangular, but large angular blocks 

 of granite, sometimes over 1ft. in diameter, were found in 

 the bed of the stream below the outcrop of the conglomerate, 

 and pointed to the proximity of the granite in situ. A collec- 

 tion of rocks composing the granite comprised, besides the 

 hard flaggy sandstones, granites of all degrees of texture, 

 granitic and hornblendic gneiss, greisen, and quartzite. 



Among the granites, the typical fine-grained grey variety 

 was well represented, but the predominating crystalline rock 

 was a coarse-grained, dark-grey-coloured granite, in which the 

 muscovite was replaced by biotite. The felspar was in most 

 cases well developed, and in some examples possessed a light 

 flesh-colour. 



In the granitic gneiss the laminated structure of the con- 

 stituent minerals was often well exhibited, even in hand- 

 specimens, and when the mica was biotite, as was frequently 

 the case, the rock possessed the characteristic schistose 

 structure of a true gneiss. The hornblende gneiss is com- 

 posed principally of hornblende and orthoclase, and might 

 perhaps be more accurately defined as a syenitic gneiss. It 

 possesses a most remarkable likeness to the hornblende-gneiss 

 rocks associated with the Lower Silurian rocks of the Mount 

 Arthur and Pikikiruna Eanges in Collingwood. They are not 



