366 GREAT SERPENTINE BELT OF NEW SOUTH WALES, vii., 



hyperstbene is decomposing peripherally in the usual manner. 

 Biotite occurs in very small .amount in minute plates. Titaniferous 

 magnetite is abimdant in irregular masses moulded to some extent 

 upon the felspar and pyroxenes. Apatite forms abundant large 

 prisms, and quartz occurs in a considerable amount in granular 

 mass in interstices. A very complete analysis of this rock by Mr. 

 Mingaye is given below. It is of particular interest as being the 

 first instance of a hypersthene-})earing rock observed in the 

 Devonian series. 



Closely related to this, but less ricli in coloured constituents is 

 the coarsely granular dolerite in Portion 61 (138-1). In this, the 

 rhombic pyroxene is entirely decomposed, and is represented by 

 pseudomorphs of talc and chlorite. Prehnite also occurs as an 

 alteration-product. The small ])atch of dolerite east of tlie kerato- 

 phyre in Portion 37, is apparently of compound nature, containing 

 both normal and albitic dolerites. The first of these is exemplified 

 by specimen No. 1 409, a coarsely granular dolerite, with a felspar 

 chiefly labradorite, though clear patclies of oligoclase-andesine 

 occur. The felspar is largely altered to prehnite. The augite has 

 been partly alteied to form chlorite, and crystals of magnetite are 

 present. Quartz and liypersthene are a])sent. 



The Alhitie Dolerites. — Tlie albite-dolerite in the occurrence 

 mentioned above is a very dear, fresh rock (No. 1378), fine- 

 grained, and with a glomero-porphyi'itic to ophitic fabric, with 

 small, fui^grained, sub-variolitic patches. The felspare give no 

 sign of zoning; they are quite fresh albite-oligoclase, and, in the 

 variolitic areas, there are skeletal extensions from the ends of the 

 crystals consisting apparently of albite. The pjn^oxene is often 

 quite undecomposed; at other times, it is replaced by chlorite. 

 There are peculiar spherulitic aggi-egates of haematite in the vario- 

 litic portions. Ilmenite occurs in small crystals. Closely related 

 to the above is the dolerite (No. 1394) occurring by the boundary 

 of the Peel River Company's Estate, a mile due south of the last 

 occurrence. Tlie felspars, though albite, are a little dusty. The 

 augite-crystals are partly chloritised, forming irregular crystals. 



