BY FRITZ NOETLING, M.A., PH.D., ETC. 87 



obvious. The implements m.ade of volcanic rocks, 

 mostly if not exclusively of Diabas, consist of rounded 

 natural pebbles, which were partly used as hammers, 

 partly turned into sacred stones, and natural pieces of 

 columnar Diabas most probably used as choppers, but 

 they were never subjected to the elaborate flaking of 

 the cherty rocks. 



The tronattas were exclusively manufactured from 

 cherty rocks, and even the untrained collector will 

 notice a large variet}- of colour. There are specimens 

 of a deep jet-black, and others of a dazzling white ; there 

 are rocks of a blood-red or a bright yellow colour; there 

 are others of a grey tinge, and those of a more indif- 

 ferent colour are too numerous to m'ention. In fact it 

 seems that all the colours of the spectrum are repre- 

 sented except that which is so common in another 

 island of the Pacific, the green of the New Zealand 

 stone implements. 



On closer examination it will be noticed that besides 

 the colour there are other differences in the appearance, 

 and after a short time the observer will be able to dis- 

 tinguish at least four different main types of the siliceous 

 rocks. These are : — 



1. Chert, or preferably called Hornstone (i). 



2. Porcellanite. 



3. Breccia. 



4. Other siliceous rocks not mcluded under the 



above headings, such as Chalcedony, Wood- 

 Opal, Fossil Wood, Quartz. 



I. CHERT OR HORNSTONE.— This is generally 

 a finely-grained rock, showing a dull lustre, but a fine 

 conchoidal fracture. Its colour varies from a light grey 

 to almost jet black. Dark grey and bluish tinges are 

 the most frequent ; light grey is somewhat rarer ; and a 

 dark reddish-brown colour is the rarest of all. On the 

 whole the colour of the hornstones is soniewhat dull, 

 and the bright tinges exhibited by the next group have 

 so far not been observed amone the hornstones. Fre- 



(i) Dana, System of Mineralogy 



