Mineralogical Description of the Island of B'ank'a. 89 



stone into extensive laminae of unequal thickness from half a line 



to a quarter of an inch. In many cases, however, they are closely 



united to the substance of the rock — they appear on the fracture 



but cannot be separated. This rock is completely siliceous, and 



exhibits not the least effervescence on the application of the 

 acids. 



The village of Kampak is situated about half a mile from the 

 discharge of this river; the banks are here elevated about twelve 

 or fitteen feet above its common level at low water. After some 

 search I discovered a spot where they were exposed by an arti- 

 ficial section; they there consisted of a stratum of red ironstone 

 formed of fragments of various figures, from the size of a pea to 

 that of several inches in length and diameter, disposed in very 

 fine sand, adhering partially by means of particles of clay ; they 

 were all rounded at their edges and bore the marks of having 

 been carried down by the stream. Alternating with this stratum, 

 and in some instances immediately under the soil, I remarked ex- 

 tensive masses of clay of a reddish ground, variegated with yel- 

 low and white ; small fragments of ironstone were often bedded 



in it. 



From Kampak, the direction of the river is winding through 



the alluvial plain to its third branch, which leads to the stockade 



of Jebus ; the profusion of vegetation along the whole course, 



extending completely to the water edge, prevents an accurate 



examination of the banks ; in several places where they were 



exposed they exhibited a black vegetable mould. The stockade 



of Jebus is built on the first elevation beyond the level of the 



river : I examined the fragments of stone which were thrown out 



in making the ditch which surrounds it ; they are of the same 



kind as those found near the river at the village of Kampak, small 



red ironstones all bearing the marks of attrition, corroded on the 



surface, flat, oblong reniform. variously excavated, perforated and 



rounded : the fracture exhibited a red or brown oxyd of iron of 



different shades, the surface was covered with a yellow cchreous 

 crust* 



The country from the stockade of Jebus to the district of the 

 mines is waving and uneven, but as it is completely covered with 

 wood and vegetables, it is difficult to form an opinion of the rela- 

 tive height of the intervening hills, which may more properly be 

 called risings. I noticed thirteen in succession on this tract. 



In the descent after the first rising, large rocks of red ironstone 

 projected from the surface, or were dispersed in large fragments 

 on the road. The fracture is very various ; in some fragments it 

 is metallic, in others ochreous or mixed ; those of the former (the 



v 







. * Th R disintegrated ironmasked rocks of the Peninsula are extremely deceptive 

 ] n this respect, often appearing like water worn gravel, volcanic lapilli, &c— Ed. 



Second Series, Vol. VII, No- 19.-Jan., 1849. 12 



