NERBUDDA DISTRICT. 267 



leave the question of the causes by which such effects have been brought 

 about untouched. 



The magnitude of the results prove that the forces at work must have 

 been great ; but little has been observed capable of suggesting any satis- 

 factory explanation of their modes of operation. 



The writer of the preceding pages feels that they ought not to be 

 published without a definite acknowledgment, on his part, of the aid he 

 has received from the Superintendent of the Survey. Commencing with 

 advice, suggestions, and encouragement in every difficulty which arose 

 while the field work was in progress, Mr. Oldham's assistance has 

 throughout ever been readily extended to him. He is more especially 

 indebted to it for the correction of some of the more glaring defects in 

 the form which he had given his paper ; and he desires to record his 

 sincere thanks for the many occasions on which he has profited by help 

 so often, and so kindly, afforded. — (J. G. M.) 



