The Lower Essequibo River and Cuyu-ni River District. 121 



character. Similar rocks are visible at the landing, whilst on the road 

 at about 150 yards east from the Manaribisi Creek, a dark-coloured 

 epidote-biotite-gneiss, intersected by veins of pegmatite, and closely 

 resembling the dark-coloured rock at Wolgar Quarry on the Essequibo, 

 occurs. 



The lowest rapid of the Cuyuni River, a tidal one known as 

 Tatruba and as Patrick's Fall, is over an aplite very similar in 

 appearance to that near Arian Island, and the same variety of rock 

 occurs at the foot of Akaio Rapids, but is there veined with pegmatite. 

 Towards the middle part of the Akaio Rapids the aplite assumes a 

 coarser texture. Near the top of the rapids the aplite gradually 

 assumes a somewhat gneissose structure, and by the development in 

 it of biotite passes into a granitite. The coarse-textured aplite was 

 noticed at Sauri, the succeeding rapids, where it is veined with 

 pegmatite. Akawaio, Steil and Tuwarong Rapids are over granitite- 

 gneiss, which at the former rapids is dark-coloured and finegrained. 

 At a small rapid above Akawaio the gneiss is coarse-textured and 

 granitic, of a dai'k-green colour, with wide bands of lighter-coloured 

 rock. From here to the foot of Crab Fall granitite gneiss occurs^ its 

 degree of foliation varying to a considerable extent. Kungler-Mamma 

 Rapids are over a pink aplitic granite. At Smiths God Rapids a 

 similar aplite, streaked by narrow veins of epidote, is exposed. The 

 aplite varies in colour from pink to a greenish-grey, and here and 

 thert^ contains pieces of caught-up gneiss. 



Matope Cataracts are over a belt of schistose gneiss, which is 

 succeeded above the cataracts by a pink aplite-granite. At the 

 cataracts in many places veins of the pink aplite traverse the gneiss, 

 and a few narrow veins of a white muscovite granite are seen. These 

 intrusions, in places, lie between and parallel to the foliation of the 

 gneiss, and in others cut across the folia at varying angles. 



The rapids above Matope are called Kettle Falls. The rocks in the 

 river below the rapids are of a pink aplite, while the rapids are over a 

 greenish-coloured gneiss intersected by veins of aplite. 



The cataracts at Arikabusa-Boy are over coarse-textured grey 

 gneissose-granitite with, in places, at the foot of the cataracts, caught-up 

 masses of gneiss, while those at Arikabusa-Mamma are over gneiss. 

 A small unnamed rapid belo\v the Kamaria Rapids is over coarse- 

 textured gneiss which extends to the lower part of the Kamaria 

 Rapids. The rocks at the head of the latter are grey gneissose- 

 granitite. Little Kamaria Rapids, which are the head rapids of the 

 series of rapids and cataracts, are over a belt of very fine-grained gx'ey 

 granitite, which, in places, is traversed by veins of a darker basic rock. 



This series of cataracts and rapids presents formidable obstacles 

 to journeying up the river : and some of them are among the most 

 dangerous to shoot of all those encountered in the reaches of the rivers 

 of the colony which are more or less regularly traversed by gold diggers 

 and other travellers. The series extends for about three and a half 

 miles along the course of the river, the difference in level between the 

 head and the foot of the rapids being about fifteen feet. As will have 



