914 FANNING AND EDDINGFIELD. 
River, and (3) Gumaus River. The Paracale River placer was 
the first exploited, and it was this placer which was selected for 
study. The samples were obtained from the dredge of the 
Paracale Bucket Dredging Proprietary Company Limited, and 
represented cleanup concentrates from which the gold had sup- 
posedly been removed. The points discussed are: (1) The geol- 
ogy of the deposit, (2) the physical and mineralogical character 
of these concentrates, (3) the physical characteristics of the gold, 
(4) the amount of free gold, (5) the amount of combined gold, 
and (6) the best method for saving the gold values. 
The method of determining these points was similar to any 
complete ore-testing examination, namely: (1) Screen tests with 
7 sizes; (2) magnetic separation of original and of each screen 
into magnetic and relatively nonmagnetic; (8) assay value of 
all products; (4) concentration tests; (5) amalgamation tests; 
and (6) cyanide tests. 
GEOLOGY. 
The alluvium of the Paracale River for the most part lies in an 
elliptical basin covering an area of several hundred hectares. 
This is mainly in granite gneiss which is bounded practically on 
all sides by diorite schist.2 The bed rock of soft, decomposed 
granite gneiss is quite regular, having a uniform slope to the 
east. The alluvium varies in thickness from 5 meters at the 
upper end to 14 meters near Paracale. 
After the formation of the vein-ore deposits* and the establish- 
ment of a drainage system, erosion continued until a condition 
of comparative inactivity was reached. This was fellowed by 
a slight uplift, after which the gold, heavy minerals, and quartz 
boulders from the veins were washed down and concentrated on 
the bed rock. At this period the erosion in general was only 
moderate, as shown by the lack of large country-rock boulders 
in the gravel deposits on the bed rock, and by the angular condi- 
tion of the gold. The presence of quartz boulders is explained 
by their resistance to weathering in a country which must have 
been rather extensively weathered before this period of moderate 
erosion took place. 
After the deposition of the gold-bearing gravels, a subsidence 
occurred, and a bed of loam and clay and a thin bed of coral were 
deposited. Following this, a slight uplift in the western portion 
of the formation occurred, which caused the deposition of a 
* Fanning, P. R., Min. Resources P. I. for 1910, Bur. Sci., Div. Min. (1911), 
21 
*[bid., 22. 
