GEOLOGICAL NOTES ON THE PIONEER RIVER BASIN. 
75 
Speaking generally the more acid types, with preponderance of 
rhyolites and sometimes the occurrence of granites (and their normal 
aplitic modifications) with which they are associated, are in evidence 
at Nicholson’s Crossing, Mirani Bridge, the southern flanks of Mt. 
de Moleyns, the N. end of Reeve’s Creek, Milton’s Knob, Banaghan’s 
Hill, Up. Balnagowan Creek to its head (and down its eastern side to 
the E. side of portion 31v parish Hampden), then from portion 1356 
Hampden along to The Leap, then along to portion 483 Bassett. 
From The Leap a spur of rhyolite runs S. to the S.E. of portion 
496 Bassett where it approaches Turner’s Sugarloaf. The rhyolite ends 
at the S.E. of portion 757 parish Bassett, giving place to a diorite spur 
which runs up past its end to Galea’s scarp. 
Obsidians associated with the rhyolite are to be seen in the cuttings 
between The Leap and The Leap Railway Station, and also on the W. 
side of portion 1051 parish Hampden and in the S.E. of portion 500 
parish Hampden; also at Mr. Peach’s home Sub. 67 parish 474 Hampden 
they are particularly interesting. 
Granophyre? occurs at the Pleystowe Railway Station. 
Aplites are found at the Quarry Hill, N.E. from Mt. Oscar and 
at the old Quarry at Mt. Bassett. 
Trachyte. 
Gibb Maitland has recorded the occurrence of trachytes at Mt. 
Yince, Mt. Jukes, Mt. Martin, and I would record here the occurrence 
of a trachy-rhyolite at Mt. Ossa. 
Granites. 
Grey Granite is found at Mt. Dalrymple and the Ben Mohr Spur. 
Other localities in which granite types occur are Kungurri, a scarp 
( running from Mt. Dalrymple S.E. to Dunwold, Connor’s Range, Mt. 
Bridgman, Mt. McBryde, Ben Mohr and Blue Mountain. At Flat Top 
II Island and Round Top Island a red granite occurs. At Eton Hill quite 
an extensive microgranite occurs. 
Sediments. 
Where the sediments of the Bowen Series are to be seen they are 
frequently markedly indurated from the effects of the later igneous 
intrusions and extrusions. 
Contacts of this nature occur at Pleystowe Railway Station, in the 
' river bed at Pleystowe, at Green Knoll Quarry, New Walkerston Quarry. 
| portion 105 parish Greenmount and on the eastern side of the stony 
| divide between Baker’s Creek water and Sandy Creek water and the 
| Boomerang Lagoon — the eastern foot of these stony ridges producing 
bog iron-ore and excellent road-binding material due to seepage. Some 
bog iron-ore is found on the eastern side of portion 1027 parish Abingdon 
' and on the extreme southeast of portion 474 parish Bassett. 
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