2(j ON HAUYNE-TRACHYTE AND ALLIED ROCKS. 



EXPLANATION OF PLATES. 



Fig. 1. — Section of trachyte showing zoned crystal of orthoclasc 

 Mount Mary, S.W. Lovett. x nicols. X 16. 



Fig. '2. — Section of melanite-trachyte with zoned crystal of 

 melanite-u'arnet. Cleary's Hill, N.W. of Lovett. Plain 

 light, x'^16. 



Fig. 3. — Section of haiiyne-aplite or haiiyne-trachyte dyke rock, 

 with large Carlsbad twins of sanidine carrying included 

 crystals of haiiyne. Groundmass = crystals of green 

 augite and haiiyne Avith allotriomorphic orthoclase fel- 

 spar. From Port Cygnet, x nicols. x 16. 



Fig. 4. — Section of trachyte from back road, two miles N.W. of 

 Lyraington. Porphyritic crystals = sanidine in Carls- 

 bad twins and zoned, plagioclase, green hornblende and 

 augite. X nicols. x 16. 



Fig. 5. — Section of haiiyne-trachyte from Livingstone Hill, N.E. 

 of Lovett, showing large porphyritic sanidines. The 

 dark liexagon on the left represents melanite-garnet ; 

 the smaller crystal below it is green augite. Surround- 

 ing these two crystals are small forms of haiiyne. 

 X nicols. X 16. 



Fig. 6. — Section of green aegirine-trachyte from beach S. of 

 Lovett. Porphyritic sanidine and augite. Groundmass 

 = rods of pale green aegirine and prisms of sanidine 

 with fluxion structure. Plain light, x 16. 



Figs. 7 and 8.— Megascopic photographs of dull tabular ortho- 

 clase (decomposed sanidine) crystals in haiiyne-trachyte 

 on Livingsfone Hill, N.E. of Lovett. Natural size. 



