982 
MANGANESE DEPOSITS OF INDIA : DESCRIPTIVE. [ PaRT IV : 
Those wlio wish for further information about the mining regulations 
in Portuguese colonies can'consult ' Portuguese Colonial Mining Laws, 
Decree of 19JG'. This is a translation of the Boletim Official do Gov- 
erno General da Estado da India, No. 84, dated October 23rd, 1906, and 
consists of 50 foolscap pages of print. This translation was made by 
Mr. R. A. Becher, His Britannic Majesty's Consul at Goa, and is dated 
Mormugao, October 1906. 
Very little seems to be known about the geology of Goa. But as far 
as I can iudse from the few exposures I saw 
Geology. . 1 • • 
round Bicholim, and the remains of rocks in- 
cluded in specimens of manganese-ores from different parts of Goa, the 
country consists mainly of Dharwar rocks, very largely obscured by a 
covering of laterite. Judging from what is known of the geology 
of North Kanara, it is not improbable that some of the hills in Goa may 
consist of gneissose rocks, but of this I have no evidence except for the 
gneisses exposed in the railway cutting at Dudh Sitgar railway station. 
On the eastern borders of Goanese territory, where it adjoins the 
Belgaum district, the country consists of Deccan Trap, this forming the 
Western Ghats. Of the rocks I have seen that are probably of Dharwar 
age the following may be mentioned : — quartzite, magnetite-, hematite-, 
and limonite-quartzites, phylHte and basic igneous rocks, as well as 
quartz-veins traversing these. 
The manganese-ores occur partly in the laterite and partly in the 
underlying decomposed Dharwar rocks. As 
Origin of the ores. . . . , 
far as 1 can tell from the three deposits visited, 
the manganese-ore found in the decompossd Dharwars has been formed 
by their superficial replacement. The laterite is of the low level variety 
and is probably, in many places, as much as -50 feet thick ; in rare cases 
it may be more, though I have not seen any such section myself. The 
laterite does not rest as a horizontal sheet on the underlying rocks, and is 
thus different in mode of disposition from most occurrences of high-level 
laterite I have seen ; for it seems to have followed the contour of the 
land, and in quarries and other sections is seen to rest on the underlying 
rock with a very irregular surface and to include fragments of this 
underlying rock. From this, and the relations of the two, it seems to 
me clear that the laterite has been formed by a combination of impreg- 
