104 VOLCANIC AREA OP EAST MORKTON, ETC., DISTRICTS, Q., 



coastal range in the early Tertiary periods. The coastline was 

 probably re-submerged so that the folded range formed the new 

 coast. The mountainous region at Woodford was lowered about 

 300 feet by erosion, leaving the lavas which infilled old valleys 

 standing in relief. It became reduced to the state of a peneplain. 

 In late Tertiary, probably Pliocene, times the district commenced 

 to rise again, and the Woodford peneplain was elevated by 

 degrees to its present position; the new coastal area was eroded 

 to the state of a peneplain, widen it is at present, in the southern 

 part, as at Oaboolture, and any Tertiary sediments deposited had 

 time to be removed by denudation. Further north, in the 

 Laguna Bay district, the coastal strip was much more recency 

 elevated than in the south, and has at present, the characteristics 

 of a raised marine plain; whilst the Cooran district has all the 

 features of a Pleistocene raised peneplain. The elevation here 

 is so recent in the Noosa and Maroochy districts that the rivers 

 and creeks flow parallel to the sea long distances before entering 

 it (see Noosa River, Bota Creek, Maroochy River in Plate v.). 

 The theory of Isostasy alone, without taking other forces into 

 consideration, can explain this recent Pleistocene and Post- 

 Tertiary elevation. The diversion of the drainage of a large area 

 into the Mary and Stanley Rivers which was once drained by 

 numerous small streams, whose positions are marked by old river 

 gravels at Cooran, Eumundi, the Glass House Mountains and 

 the D'Aguilar Range, would lead to an elevation in their former 

 areas of deposition. The diversion of the drainage was, however, 

 in my opinion, aided by an uplift along the axis of the present 

 coastal ranges. The courses of the Mary and Stanley Rivers 

 parallel to the Blackall and D'Aguilar Ranges are an interesting 

 study. The Mary River, between the Conandale Range and 

 Kenilworth, flows in a narrow V-shaped valley through hard 

 granitic rocks, broadening at this point to a U-shaped valley with 

 a meandering stream, flowing through softer phyllites. The 

 whole stream pursues in general a subsequent course, but 

 accidents of surface, like basalt masses, have induced slight 

 departures from the direct path. The stream above Kenilworth 



