METAMORPIIIC SERIES. 31 



Before proceeding" to the detailed account of the above sedimentary 

 formations under the headings of the different fields in which they occur, 

 it will be well, with the aid of the accompanying small-scale map, to 

 indicate generally the extent of their distribution so far as it is known 

 throughout the whole area, and to point out the resemblances and 

 relations which exist between the deposits of identical age in more or less 

 widely-separated localities. But first it will be necessary to give a 

 general sketch of the crystalline or metamorphic rocks which, form 

 the floor of the basins or troughs in which the more recent rocks have 

 been deposited. 



Section 1. — Metamorphic Series. 



A considerable number of observations on these basal rocks have 

 been accumulated during the season, in consequence of its having been 

 necessary to make traverses in various directions, in order to examine 

 deposits of iron ores at a distance from the coal fields, and also for the 

 purpose of searching for outlying areas of sedimentary rocks. Although 

 the observations made under these circumstances are therefore of a some- 

 what disconnected character, sufficient has been seen to show that the 

 detailed examination of these rocks will not improbably throw much light 

 on the origin of the leading structural features of the country. 



So far as is certainly known, the metamorphic rocks of this area belong 

 to but one great series, but there are some marked features in the distri- 

 Distribution of litho- bution of the several lithological varieties. In the 

 logical varieties. ^^g^^ massive granitic rocks with abundant veins 



of pegmatite and epidotic granite prevail. In association with them 

 there is an enormous thickness of crystalline limestone which will 

 presently be described. The economic importance of this rock will also 

 secure for it some further notice in the proper section. 



Towards the centre of the area, west of Munkah, there is a complete 

 „ , , ,. , change in the character of the rocks. Hornblendic 



Hornblendic rocks. 



gneisses are there the most common form met with. 



Many of these have a markedly trappean aspect, and are sometimes not 



( 31 ) 



