TRAVELS IN BRAZIL. 117 



north of Mandu, similar overflowings caused by 

 the rising of the Rio Servo. The woody tracts were 

 inundated to the depth of four to six feet, and the 

 road, whicli was also under water, was gullied into 

 deep holes. As it was necessary to lead every 

 mule through separately, we were unable to pro- 

 ceed on this day more than three leagues, at the 

 end of which we reached the pleasant hill on which 

 stands S. Vicente, a small place consisting of a few 

 houses. But here we were first assailed by a 

 new torment, namely, the tick (^Acarus), an ugly, 

 flat, brownish insect with a sliarp proboscis, of 

 which there are several kinds, some not bigger than 

 the point of a needle (Carabato miudo), and others 

 considerably larger ; the latter, l)y continual suck- 

 ing horses and horned cattle, often attain half the 

 size of a hazel nut. The inhabitants erroneously 

 consider both the large and small to be of the 

 same species, differing only in age. They generally 

 cling unseen in thousands to the blades of grass, 

 and, at the slightest touch, attach themselves to 

 the traveller, and give him inexpressible uneasiness 

 by the violent itching which they create. 



To the north of Rio Servo, and about two miles 

 from Mandu, we perceived the first traces of gold- 

 washing. The rock is a quartzy, white or whitish 

 green mica-slate, which here and there shows a 

 dip from S.W. to N.E., and upon it lies a consi- 

 derable mass of red heavy loam, from which the 

 metal is washed. The mica-slate, in which there are 



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