340 Albert V. James : 



Sum mar I/. —The inicroscopic examination of the kaolin gives no 

 definite evidence in favour of either theory, but the field evidence, 

 Avhile producing little positive evidence in support of pneuma- 

 tolysis, strongly discounts the meteoric theory. The fact that no 

 fiuor, cassiterite, or topaz is found in the kaolinized rock, and only 

 a small amount of tourmaline, rather suggests that we must turn 

 to magmatic water and carbon dioxide as the agents causing 

 Jcaolinization, as in Cornwall and in. the United States (12). The earthy 

 calcite in the sections of the kaolin supports this conclusion. 



Economics. — -Fifty years ago a company was formed to export 

 this material to England, Avhere it wa.s bought at 18/- per ton. 

 ■Owing to the lieavy transport cost the company failed. 



At present the kaolin in Q^ and Qo is being worked by Corn- 

 "vvells, who use it for making fire bricks and other articles used at 

 higli temperatures. There is a growing export trade in these 

 manufactured articles. 



On account of the trace of iron in the Bulla kaolin, it has not, up 

 to the present, been used for chinaware. The quantity of kaolin 

 ;appears to be uidimited. 



Kainozoic Rocks. 



Older Basalt. — In the south-east of the area three lenticular out- 

 -crops were found. The most northerly is vesicular, and rests 

 <lirectly on Silurian sediments, and underlies a very thick cap of 

 stratified Kainozoic grits. The best section, however, is seen in a 

 -cliff face in the extreme south-east, where very decomposed older 

 basalt overlies a pre-older basaltic river conglomerate, about 8 ft. in 

 thickness, wliich merges into sands at the sides. This sand and the 

 sandstone conglomerate beneath the basalt are strictly local in 

 origin, and remind one very much of the sands underlying and 

 overlying the leaf beds two and a-lialf miles to tlie N.N.W. 



In this decomposed basalt there are. in situ, several undecom- 

 posed basaltic nodules. These remove all doul)t as to the identity of 

 the outcrop. The basalt thins out at the edges, and here the under- 

 lying sand has in part been altered to quartzite, and the overlying 

 sandy clay to a rock resemVjling red brick. Newer basalt more tlian 

 100 feet in tliickness rests on these beds. 



Pre-oldcr-hasalf Hirer Val/ei/. — Tlie alignment of the tliree 

 southern outcrops is indicative of an old. river valley, and this 



