186 THE CONCAVE STONE IMPLEMENTS, ETC., 



habits of the native, one groove was made, it was used, and 

 the stone then dropped. The following table was made from 

 a random 100 concave scrapers: — 



Concave scrapers with 1 groove .... 44 per cent. 



2 grooves . . 20 „ „ 



3 or more 



grooves . . 36 „ „ 



As many as six grooves I have found on one stone, but 

 such a large number is uncommon. 



Amongst the Victorians large numbers of the smooth 

 grooves are the rule, whereas almost invariably single con- 

 caves are found where a pebble is used, and worked grooves 

 are either single or not numerous. 



MATERIAL. 



Any material, just as any implement, may serve the 

 Tasmanian in making a concave scraper; but by far the 

 commonest in use is the blue-black metamorphic mudstone, 

 called hornstone by some writers. 



This stone has the peculiarity that its surface, in cer- 

 tain conditions, alters. It changes with decomposition to a 

 light buff colour, but it still remains hard and its outlines 

 are still sharp. It is not a real patina, but a decomposition 

 of the rock. Some implements, that I have, are heavily thus 

 patinated, but have other concave grooves worked in them 

 that are blue-black and sharp (Fig. 7>. 



The difference between the age of the grooves covered 

 with patina and those grooves with no patina would be 

 interesting. 



Unfortunately, the patina is acquired in varying times 

 according to the moisture, etc. 



All one can say is that some considerable time has 

 •elapsed since the first chips were made. How long we can 

 ^uess at, but a guess it must remain. 



EXPLANATION OF PLATES. 



Plate XXVI. 

 Fig lA. Fig. 2B. Fig. 2A. Fig. 2B. 



Fig. 3. Fig. 4. Fig. 5A. Fig. 5B. 



