550 Harry Page Woodicard — Geology of Western Australia. 



appearing beneath the Paleeozoic formation. The rocks of this belt 

 consist mostly of hornblende, mica, or talc schists, of which the 

 hornblende schist so closely resembles diorite that it is impossible 

 to distinguish it in a broken specimen. 



The rocks of this belt are a good deal broken and faulted by 

 granite and diorite dykes and quartz lodes containing gold, iron, 

 and copper. There are also some large magnesia lode-masses rich 

 in fine gold, which will probably prove to be serpentine at a depth. 

 Many of the lodes also contain large quantities of chlorite. 



The fifth or second granite belt is about the same width, and 

 similar in every way to the first mentioned. It extends from the 

 south coast, following the line of the first auriferous belt north, 

 and, like it, dipping under the Palaeozoic table-land of the Eortescue. 

 Only a small portion makes its appearance on the northern side on 

 the Yule River near Pilbarra upon the north-west coast. 



The sixth or second auriferous belt lies next, and at present its 

 width is unknown, but it is certainly of considerable width in places, 

 and has proved wherever prospected to be extremely rich in gold. 

 It extends north from the Dundas Hills (where this formation first 

 outcrops from below the sand-plains) by Wagemulla, Coolgardie, 

 the Three Pinnacles, Ullaring, Lake Carey, and following about the 

 same line as the other belts, and turning with them to the north- 

 west by the Nullagine, Marble Bar, Pilbarra, Egina, and Mallina 

 upon the north-west coast. 



The rocks of this belt are generally very similar to those of the 

 first auriferous belt, but the formation and lodes are a great deal 

 more faulted and broken ; however, to make up for this they are the 

 richest that have ever been discovered. 



The hornblende rocks of this colony are very remarkable in 

 character, being met with most abundantly from north to south. 

 They vary immensely in colour, structure, and external character, 

 some at first glance having the appearance of clay-slate, but on 

 being fractured they exhibit a structure similar to diorite, whilst 

 others again only contain green crystals of hornblende disseminated 

 through a quartz matrix or have a jade-like appearance, which latter 

 variety are continually being mistaken for copper, nickel, or silver. 

 With these rocks are associated the principal mineral deposits of 

 the colony : gold, tin, coppei", antimony, lead, zinc, manganese, 

 and iron. 



Igneous. 



Volcanic. — No active volcanoes are known to exist in this colony, 

 but as many volcanic [Ohsidian) bombs have been discovered in the 

 far north and in the interior, and large basaltic flows exist, extinct 

 volcanic craters may occur, as has been stated. On the north-west 

 coast, south of the Nullagine, and on the Fortescue Eiver there are 

 several lava-flows, but the largest development takes place in the 

 Kimberley district, where a flow stretches from the east side of 

 the head of the Ord Eiver far into the northern territory of South 

 Australia. At Bunbury, and one or two points on the coast around 

 the south-west corner of the colony, columnar basalt occurs. 



