DETAILED DESCRIPTIONS OF THE RESrECTIVE COALFIELDS. 43 
The system of mine inspection at Giridih and the measures taken 
to provide for the safety of the workmen are probably equal to 
the best mining practice of Europe. Whilst the excellent housing 
accommodation, the facilities for the acquisition of small parcels 
of land by the workmen, and the establishment of excellent and 
well-attended schools and well-equipped hospitals reflect the 
greatest credit upon the engineers engaged in the development of 
the coalfield. 
Raniganj} — The Raniganj field is the largest of the coal- 
fields now being worked in India. It is situated from 120 to 140 
miles north-west of Calcutta, and the East Indian Railway Com- 
pany's line passes through it centrally. The Bengal-Nagpur Rail- 
way Company also have access to the coalfield, and besides these 
trunk lines there is a growing net-work of branch lines and sidings 
for the service of the collieries. 
The extent of the exposed coalfield is approximately 500 square 
miles, within which area the Panchet, Damuda and Talchir groups 
attain an aggregate thickness exceeding 11,000 feet. The general 
dip of the beds is towards the south at angles of from 5° to 20° 
and the measures are abruptly cut off at the southern boundary 
by a fault the throw of which must, at the least, be equal to the 
full thickness of the beds. On the east the coal measures dip 
under the Gangetic alluvium, and the boundary of the field is 
unknown. Recent borings, however, point to their extension eastwards 
to a very great distance, but overlain by the higher beds of 
the series, and at a considerable depth. There are numerous 
faults and dykes, most of which are obscured by the alluvial cap 
which covers so much of the coalfield, so that their presence is, 
as a rule, only disclosed during the course of mining operations. 
Much remains yet to be done in the unravelling of the fault 
structures and the correlation of the coal-seams, and a special 
committee of members of the Mining and Geological Institute is at 
present engaged upon this work, and will shortly publish a revised 
edition of Dr. Blanford's original map of the coalfield. The dykes 
are of mica-peridotite and basalt. The principal intrusion is the 
great Salma basaltic dyke, which has a thickness of 120 feet, and 
^ Blanloid; Mem., G. S. I., Ill, Art. 1 (1863). 
