CHAP. 3. | GENERAL CLASSIFICATION OF ROCKS. 41 
patches, which cannot always be absolutely traced into correct relation 
with each other, being only left on either side of this covering. 
Under this disadvantage, the following groups of beds are advanced as 
representing the order of their superposition ; while it will be seen how 
this arrangement has been adopted when the rocks are more particularly 
described. The series consists of four different groups of slates and 
quartzites, the slates being in two of these largely associated with lime- 
stone strata and with trappean rocks and their associates. The three 
lower of these groups are separated by unconformity and overlap, but 
the separation of the fourth is not at all so clear. The following is the 
proposed scheme of succession :— 
( Kistnah Beds... .. Sreeshalum quartzites. 
hi slates. 
Nullamullay Beds ۱ 
Byrenconda quartzites. 
j 1 Poolumpett slates. 
| Chey-air Beds jos 
Naggery quartzites. 
KADAPAH FORMATION. 
E lulu Vaimpully slates. 
eds u: s 
" i LU Gooleheroo quartzites. 
The names of the different groups and sub-groups have been 
selected either from the prineipal mountain-ranges, rivers, or villages. 
