ULLOA*S VOYAGE TO SOUTH AMERICA. 55 1 



I was at that village, faw fome of thefe fparks in their natural ftate ; and both their 

 colour and hardnefs fufficiently fhewed that they were of a very fine fort. 



Another kind of ftone is found in great plenty all over this country. It is of a fine 

 green, and harder than alabafter, though not pellucid : but no more valued than any 

 of the former ; except that a few toys or utenfils are made of it. 



Here are alfo fome mines of fulphur, and fome parts afford vitriol ; but no farther 

 known than as Nature has placed them in view ; not only the improvement of them 

 being entirely neglected, but fcarcely any notice taken of thofe which lie on the furface 

 of the ground ; either becaufe the inhabitants ftand in no need of thofe minerals, or 

 from their llrong averfion to any thing that requires labour. 



North of Quito, betwixt two plantations, at the foot of mount Anlagua, one of 

 which bears the fame name, and the other that of Courogal, runs a very large river, 

 which petrifies any wood, leaves, &c. thrown into it. I have had whole branches thus 

 petrified ; and the porofity of the ftem, the fibres of the rind, even the fmallefl veins 

 of the leaves, and the meander of its -fibril, equally difcernable as when frefh cut 

 from the tree. I have alfo had large pieces of timber petrified, which at firlt fight ap- 

 peared to be wood thoroughly dried j no vifible alteration having been made in them, 

 except in colour. 



With all thefe appearances, I cannot think that the wood, leaves, and the like, 

 which are put into the river, are really turned into ftone of fuch a hardnefs as that I 

 experienced : but as the appearance is undeniable, I fhall offer an explanation of this fup- 

 pofed tranfmutation. 



It muft be obferved, that the rocks and all the parts which this river walhes, are 

 covered with a cruft of hardnefs little inferior to that of the main rock ; and this in- 

 creafes its volume, and diftinguifhes itfelf from the original rock, which is fomething 

 yellowlfli. The inference I would draw from hence is, that the water of the river 

 is mixed with petrifying, vifcid, and glutinous particles, which adhere to the body 

 they furround : and as by their extreme fubtllity they infmuate themfelves through 

 its pores, they fill the place of the fibres, which the water infenfibly rots off and fepa- 

 rates, till at length all that was leaf or wood gives way to that petrifying matter ; which 

 ftlll retains the impreffion of the parts of the original, with its feveral veins, fibres, and 

 ramifications. For at the time of its infinuation, the du<5ls of the wood, or leaves, ferve 

 for a kind of mould, by which it naturally takes the entire figure of the body into which 

 it has obtruded itfelf. 



An obfervation I made v/ith fome branches confirms me in this opinion : for, having 

 opened them, I found fome leaves and bits of wood, which fnapped on breaking ; and 

 the infide was as large as real ftone, the texture only remaining of its firft fubftance. 

 But In others, the parts confolidated by the ftony matter fnapped ; and the fibres, not 

 having yet undergone a total corruption, retained the appearance of wood, though fome 

 were more rotten and decayed than others. I had alfo fome leaves, the furface of which 

 was only covered with a very fine lapideous tegument, but within were entire leaves, 

 except here and there a httle mark of decay. ^ 



It is to be obferved, that this matter much more eafily faftens on any corruptible 

 fubftance, than on the more compact and folid, as ftones, and the like : the reafon of 

 which is, that in one it meets with pores, in which it fixes itfelf ; but h.iiving no fuch 

 hold on the harder bodies, it Is foon wafhed off by the agitation of tiie water ; that if 

 now and then fuch crufts are feen on ftones, they never make any fenfible addition to 

 their volume, though fome excrement is nov/ confpicuous from the difference of the 

 colour } that of the petrified leaves, both within and without, is of a pale yellow j and 



the 



