TUh] HARAKAHS. 
180 
The third modo of occurrence of the coal seams is in streams 
of low fjradicnt, frequently largely alluvial, as 
Ooal outcrops in Rcntio Dhuneti Nala near Chutra. In such a 
stroama. . , , 
case the coal seam, usually with gentle dip, 
may form a small outcrop projecting above water or sand, or ' may 
extend as a flat outcrop for many yards. 
Now let us consider the coal seams themselves. Those occur- 
ring in a given horizon may be cither single or two or more in 
„ , , ■ , number, separated one from another by one or 
Number and tliu kncws ' r J ^ 
of ooal soanis in one niorc of the rocks enumerated on page 177. 
They may vary in thickness from an inch 
up to some 12 feet. As examples of a single thin scam mention 
may be made of the 9 inch seam of Biyah Mandha Nala (Sanhat 
field. No. 4), and a 4 inch seam in the Chirra Jharia (Kurasia, 
No. 10) ; whilst as examples of a single thick seam mention may 
be made of the Bijaura Jharia (Kurasia, No. 7) 9 foot (? 15 feet) 
seam, the Gorghela Nala 8 foot seam (Kurasia, No. 4), and the 
Balbahara 10 foot seam (Sanhat, No. 18). For the extremes 
amongst multiple seams we may notice the lowest horizon in 
Gorghela Nala (Kurasia, No. 1), where 9 seams totalling only 30 
inches occupy a total thickness of 23 feet 8 inches and the Karar 
Khoh section in the Kaoria Nala (Kurasia, No. 33), where 7 seams 
totalling 36 feet occupy a total thickness of 47 feet. 
We may now notice the characters of the coal. It is of the 
typical Gondwana banded habit, consisting of 
Characters of the coal. . . r i • i i 
various proportions ot bright and compara- 
tively dull coal. The bright coal is the purest, and, judging from 
its brilliant conchoidal fracture, is of the nature of a colloidal 
substance which has in some way segregated chemically from the 
admixed earthy materials that give rise to the greater proportion 
of the ash of the coal. This is well illustrated by the proximate 
analysis of a picked pure material from Daukihuri (Kurasia, No. 6) 
given below in Table No. 1. 
This bright material usually occurs in bands from | to | inch 
thick, but is sometimes 1 or even 2 inches thick. It is very 
brittle, faUing to pieces readily ; it usually alternates with the 
dull coal, but bands are occasionally found consisting entirely of 
bright coal up to a thickness of 6 inches. One variety, rather rare, 
consists of very thin alternating bright and dull laminae, the coal 
having a general bright appearance. A specimen of such coal 
from Balbahara showed a specific gravity of r51, whilst a piece 
