140 BANIGANJ COAL FIELD. [ChAP. VIII 



III. Alluvium. 



There are several forms which the various loose surface deposits of 



the Ganges delta and its neighborhood assume, 

 Various kinds. 



each form probably corresponding to a distinct 



origin. Those covering and concealing the rocks of the Raniganj 



basin consist principally of three kinds. 



1. Modern Alluvium, including the recent deposits from rivers, 

 and the river alluvium of the Delta of Lower Bengal. These consist 

 of sands and sandy clays, and cover but a small extent of country. 



2. Old Delta Alluvium. This spreads over a considerable area, 

 and the Damudas and their associates disappear beneath it at the 

 Eastern boundary of the known coal-bearing area. In some places 

 it appears to contain gravelly laterite, in others it unquestionably over- 

 lies the laterite unconformably, and fills valleys, as that of the Singa- 

 ran, from which the laterite has been denuded. In some places, as to 

 the South-east of Ukra, and over a considerable area on the West 

 flank of the ridge, extending North from near Khyrasol, the alluvium 

 contains large deposits of mottled clays and coarse gravel, beds of quartz 

 pebbles occurring in places. 



But little is seen of either of the preceding formations within the 



Haniganj field ; their history and relations are now being traced out over 



large areas, and by such means alone can they be fairly understood. 



• S. Old Biver Alluvium. The neighborhood of the Barakar and 



Damuda is covered in many places by considerable masses of gravel, 



with occasional sands and clays. They are well seen between the 



Ntinia and Damuda, near their confluence, and along the North side 



of the Damuda, in the neighborhood of Hirapur. They are frequently 



.• , , , highly kunkuriferous, especially to the West, so 



Calcareous bed with ° J x J ' 



shells, that South of the Damuda, near Hirakund ; near 



Hatinal, South of Chirkunda, and around Ramnagar,* (the last three 



* Noticed by Mr. Williams as fresh-water limestone, with Unios. — Report, page 89. 



