4 86 NOTES OF A BOTANIST CHAP. 



from any accidental hollow at first and then con- 

 tinually deepened by the pebbles and sand whirled 

 round and round in them by the surging and eddying 

 waves of the cataracts during the season of flood. 1 

 Although we have no elements wherefrom to 



o 



determine positively the date and mode of execution 

 of the picture-writings, those questions seem to me 

 to have been involved in unnecessary mystery. 

 The instruments used in scraping such deep lines 

 in the granite were probably chips of quartz crystal, 

 which were the hardest cutting-instruments pos- 

 sessed by the aborigines of South America. In 

 the Amazonian plain I know of but two extensive 

 deposits of large rock-crystals one of which is a 

 good way up the Rio Branco, and the other is at 

 the foot of Mount Duida, near the village of Esme- 

 ralda, therefore in the immediate neighbourhood of 

 the Casiquiari. I know also of but one such deposit 

 on the Pacific side of the Andes, namely, in the 

 hills of Chongon near Guayaquil ; yet pieces of 

 quartz, some of which have served as knives, others 

 as lance- or arrow-heads, are found strewed about 

 the sites of ancient towns and settlements through 

 several degrees of latitude. Whatever the instru- 

 ment used by the Indians of the Casiquiari, it is 

 difficult to assign any limit to the time required for 

 the execution of the figures ; but any one who has 

 seen an Indian patiently scraping away for months 

 at a bow or a lance before bringing it to the desired 

 symmetry and perfection, or who knows that it has 

 taken a lifetime to fashion and bore the white 



1 [The supposed tracks of animals are doubtless works of art like the other 

 figures, probably clue to a desire to imitate the well-formed impressions of feet 

 that the hunter must continually meet with during his search for game. ED.] 



