ON THE GEOLOGY OF WEST MORETON, QUEENSLAND. 141 



The second period of movement produced the Fassifem 

 Block lying to the east of the Little Liverpool Range and 

 the approximate collinear portion of the main range to the 

 south of the junction. This fault probably amounted to 

 about 900 feet. The throws of these faults have been 

 calculated from the following evidence : — 



i. The mature topography of the main range near Too- 

 woomba is continued to the east near Spring Bluff at a 

 lower level of about 500 feet. 



ii. At the main range near Toowoomba basalt caps the 

 coal measures at an altitude of 1,700 feet above sea level. 

 It can be clearly seen from the railway line at the ninety- 

 three mile post from Brisbane. Throughout the Lockyer 

 Block a similar flow of basalt up to 600 feet in thickness 

 caps the coal measures in each of the four ridges at a 

 height of 1,200 feet above sea level. 



iii. At Mount Walker, a peak belonging to the Passifern 

 Block, basalt also caps the coal measures, but at a height 

 of only 300 feet above sea level. 



This evidence is supported by the appearance of the 

 sandstones and grits of the coal measures in the railway 

 cuttings along the main range and the Little Liverpool 

 Range. At the ninety-one mile post near Spring Bluff 

 the slickensided surface of the fault scarp can be clearly 

 detected. Between the first and second railway tunnels 

 in the Little Liverpool Range a marked change in the dip 

 can be noticed along the line of fault, and slickensided sur- 

 faces were found in the grits and sandstones. One mile to 

 the west of Ipswich the coal measures are tilted at an 

 angle of 80°, and the Bremer River follows the line of fault 

 for a distance of over two miles from Berry's Lagoon to 

 Coal Palls. 



