340 



E. C. Andrews has favoured me with a list (more detailed than that already 

 given) of geolcols in south-eastern and eastern Australia, as follows : — 



1. Murray River depression — sea-level. 



2. Woodend Gap, 1,000 feet above sea-level, Bendigo line. 



3. The Kilmore (Victoria) gap or geocol is about 1,200 feet above sea-level, and a 



few miles wide. The Melbourne express passes it about 60 miles from 

 Melbourne. Between Kilmore Gap and Hunter River there are numerous 

 long meridional depressions in the Southern Plateau. These are not 

 cross gaps. 



4. The Cooma or Monaro geocol, New South Wales (or Australian Rift, as Taylor 



has it), is about 2,000-2,600-3,000 feet above sea-level, is of fair width, and 

 stretches from Omeo through Bombala to Cooma. 



5. The Lake George geocol, New South Wales, is about 2,000 feet above sea-level. 



6. The Cassilis or Hunter geocol, New South Wales, is about 20-30 miles broad, 



and 1,700 feet above sea-level, and is responsible for the long dry loop 

 extending from Gilgandra almost to Newcastle. 



7. New England from the head of the Allyn, the Chichester and the Paterson, to 



Cunningham's Gap (2,000 feet) in South Queensland, presents an excessively 

 rough and high plateau front to the coast, 



8. Another broad gap occurs near Toowomba, Queensland, and is traversed by 



the Brisbane train from Toowomba to Warwick. Greatest height, 2,000 feet. 



9. The Rockhampton-Longreach Railway, Queensland, also traverses a gap about 



1,500 feet in height. Its width is not known to the writer (E.G. A.). 



10. The Cairns-Chillagoe Line, Queensland, rises on to the Kuranda Gap (1.100 



feet), which is in the form of a broad valley lying between plateaux on each 

 side. Heights from 4,000-5,000 feet, 1,100 feet at Mareeba. 



11. The Townsville-Charters Towers Railway, Queensland, also passes in a deep 



wide valley of low height between high ranges. Height about 1,000 feet. 



The number of gaps or geocols has not yet been determined, but it is desirable 

 to draw attention to their importance in regard to the distribution of plants. The 

 writer (J.H.M.) has specially worked at the Cassilis geocol in this connection, and has 

 a considerable list of western New South Wales plants which have used this gap for the 

 purpose of migrating towards the coast. The migration in a contrary direction has been 

 less worked out. 



GEOLOGICAL FORMATIONS. SOILS. 



With Some Incidental References to Climate. 

 The mineral character of soils on which plants will thrive cannot be absolutely 

 decided by the quantity of any substance such as silica, calcium carbonate, or sodium 

 chloride, which may be found in their ashes. The physical nature of the soil, i.e., its 



