Daintree. — On the Structure of certain Igneous Rocks. 459 



patches appear to be cavities filled with the fine-grained basaltic portions of the 

 rock. 



No. IX. — (Snowy Peak Range.) Similar to No. 2076. 



No. 410. — (Ilaurata District.) This rock differs from those classed under 

 this head, as orthoclase and plagioclase are both present. The brown mineral 

 is probably augite ; the colours, however, as seen in polarized light are far less 

 brilliant than usual. 



The base contains an immense number of microlites, and exhibits well the 

 " fluidal" structure. Under a \ inch objective the microlites appear of a clear 

 yellowish brown ; they are probably augite. 



No. 218.— f Flagstaff Hill Basin.) This specimen consists of a fine- 

 grained matrix composed of small grains and crystals of augite, plagioclase, 

 and magnetite, in which larger crystals of olivine are imbedded. 



No. 398. — (Haurata District.) Contains the same minerals as No. 218, 

 together with slender acicular crystals of apatite. 



The olivine has been much decomposed, and hydrous ferric oxide in some 

 cases only remains. 



No. 204. — (Acheron Section.) A weathered specimen. The felspar is 

 very much altered ; some appears to be orthoclase. There are many long 



of the prisms. 



ansverse 



Trachytic Rocks. 



No. 308.— (Mount Misery,) Contains crystals of quartz and orthoclase 

 in a compact felsitic base. 



No. 358.— (Snowy Peak Range.) A similar rock of greenish colour. In 

 addition to the quartz and felspar it contains a few garnets. 



No. 359.— (Snowy Peak Range.) This 



mass when in motion at the time of eruption. 

 No. 366.— (Snowy Peak Range.) This i 



Tushing 



grains of garnet, and a little brown mica. It exhibits 



structure very 



i between 

 Granitic. 



No. US.— (Snowy Peak Range.) Consists of orthoclase, a considerable 



silvery 

 structur 



the specimen and section. It is evidently a secondary formation, filling spaces 



between 



It is probably prehnite. 



Pitclistones. 



No. 349.— (Snowy Peak Range.) Contains crystals and crystalline grains 



