167 FERMOR : GEOLOGY AND COAL RESOURCES OF KOREA, C. P. 
CHAPTER V. ; . 
THE TALCHIRS. 
As has already been stated, the principal portion of the southern- 
y ^ most or Kliar<fa()n |)latean of Korea State is 
occupied by the Talchir formation. In a 
general way these Talchirs agree with the typical Talchirs of the 
country further to the east, being composed largely of shales, usually 
j^.^^ J greenish or blackish, but sometimes dull pur- 
> o ogy- plish, with or without scattered boulders and 
pebbles. Interbanded with these Talchir shales there are frequently 
thin courses, averaging 3" to 1' thick, of a very fine-grained limestone 
(see Plate 22, fig. 1). There are .also ovoid masses of similar 
limestone up to a yard long, which are almost certainly of secondary 
origin, probably formed by concretionary action accompanied by 
replacement of the shale. These limestones are well seen where 
the track from Jaraunda to Phunga crosses the Budra Nala. Some 
of the shales at this point are traversed by an intricate net- 
work of thin veins of calcite evidently of secondary origin. Travers- 
ing the black shale there are also seams of fibrous calcite up 
to an inch thick, whilst an immediately adjoining band of hme- 
stone contains dull black remains of shale pointing to the formation 
of the limestone by replacement of the shale. 
Throughout the series there seems to be a great abimdance of 
boulder beds in which the matrix is usually shaly, but not infre- 
quently very sandy. The pebbles and boulders are composed of 
a great variety of materials some obviously local and some exotic. 
The local boulders consist, of course, chiefly of varioi;s gneisses 
and granites, and in some places near the junction between the 
Talchirs and the underlying Archseans, blocks of some particular 
variety of gneiss or granite become so large and numerous that 
it is difficult to determine whether one is looking at the actual 
summit of a buried Archaean peak, or at loose blocks of the 
Archaean rock shifted only a small distance before being incorporated 
in the Talchirs. The fragments that are obviously of exotic origin 
are not usually larger than 1 foot in diameter, and are frequently 
quite small pebbles. Amongst the foreign materials are varieties 
of quartzites, a certain proportion of pebbles obviously derived 
