BY W. G. WOOLNOUGH. 439 



miles from the top of the delta, and over 40 from the sea, proves 

 that the elevation is not an extremely recent one. The evidence 

 of the reef at the river mouth has already been commented on. 



From Viria onwards the river valley becomes practically 

 a gorge. No very extensive patches of alluvial are met with, and 

 the soapstone cliifs rise to heights of 200 to 300 feet almost 

 from the water's edge. The smaller tributary valleys do not 

 enter the river " at grade " but yield cascades falling into the 

 main stream. Even moderately large creeks are interrupted 

 by picturesque waterfalls at no great distance above their 

 junctions with the river. The larger tributaries are at grade. 

 The small valleys have thus the character of hanging valleys, 

 and indicate the youthfulness of the stream, 



I followed the Wainibuka a little above the junction of the 

 Wainimala in order to examine the nature of the gravels brought 

 down by the former stream, but found that there were none. 

 The natives informed me that this river is singularly destitute 

 of gravel for a very considerable distance. This shows that the 

 whole of the country drained by it is a continuation of the soap- 

 stone plain, uninterrupted b}'- areas of volcanic or plutonic rock. 



In the Wainimala, up to the town of Serea, level-bedded soap- 

 stones similar to those described above, form the banks, but, 

 unlike the Wainibuka, there are extensive and varied gravels 

 consisting of rock types met with in sifAi further to the west. 



Above Serea strongly marked dips are encountered in the 

 soapstones {vide p. 438). 



I searched carefully for fossils in all the soapstones, but found 

 very few traces of macroscopic organisms. The lignified plant 

 stems of Naduruloulou were referred to in my last paper. In 

 addition to these, ill-defined plant fossils were found just above 

 the first rapid of the Wainibuka. 



In general character and in elevation these soapstones are 

 comparable with those in Suva. If the rocks here are con- 

 temporaneous with those of Walu Bay near Suva, then we may 

 form some idea of their age. In the latter case they are not 

 newer than Pliocene, and may be Miocene. For topographic 



