194 Information respecting Scientific Travellers. 



This river flows, ojiposite the island Smataca, into the Orinoco, and 

 is another instance of a remarkable connexion between the tidal 

 rivers of this coast. 



There is no doubt that the Amacura is navigable for smaller ves- 

 sels and steamers to the Yarikita ; the bar at its mouth, and the in- 

 considerable breadth, which seldom amounts to more than 300 yards, 

 render it unfit for larger vessels. It abounds in that delicious fish 

 morocotto. 



It was late in the evening before we reached the mouth of the 

 Amacura. We arrived on the 10th of June at Cumaka, where, to my 

 great satisfaction, I found the invalids mostly restored, and Mr. Su- 

 perintendent King rejoicing in his recovered eyesight. 



Although the rainy season has for some time past set in, and al- 

 though our stores are materially reduced, and we have been deprived 

 of many comforts, I yet deem it my duty to persevere, and continue 

 the survey to the Cuyuni. 



Demerara, August 1841. 

 The party under my command left Cumaka, where we had so- 

 journed for some time, on the 15th of June, and having arrived at the 

 junction of the Aruka with the Barima, we continued the ascent of 

 the latter river in an east-south-eastern direction : we reached, next 

 day, its junction with the Kaituma, which falls in on the left bank 

 from the S., and is at its mouth about 200 feet wide. The Kaituma 

 is inhabited by Warran and Waika Indians, and is connected with 

 the Upper Barima by several intermediate brooks. 



Numerous rivulets join the Barima on both its banks ; some of 

 them inhabited by Warrans. It has still, however, the appearance 

 of a tidal river, being margined by mangrove and curida bushes, over 

 which manicole and truli palms raise their heads. Its banks form 

 continued swamps, which only can be made arable through the in- 

 dustry of man. 



I always considered it my dut}', wherever an opportunity offered, 

 to observe how far the geological structure of the country might be 

 favourable to cultivation ; it being undeniable that the quality' of the 

 soil depends generally upon the rocks which form the strata below 

 the arable land. The superstrata at the hills of Warina consist of 

 ochreous clay, intermixed with mould, pebbles, and that due propor- 

 tion of sand which would particularly qualify it for the cultivation of 

 coffee. The large blocks of ferruginous clay which lie dispersed on 

 the surface ensure the necessary moisture for the cultivation of that 

 plant ; for it is well known to the agriculturists how beneficially such 

 blocks operate on the soil on which they lie, contributing not only 

 to the retention of moisture, which would otherwise evaporate, but 

 to the precipitation of atmospheric vapours. 



Since we had left Warina, our course up the Barima lay more to 

 the S.W. : the banks of the rivers became higher ; while the palms 

 and mangrove bushes, which till now had been so numerous, became 

 less frequent, and were replaced by a more varied vegetation. Our 

 Indian guides informed us that, by ascending the rivulet Yarumuku 



