REPORTS OF RESEARlH COMMITTEES. 327 



recognised in various localities by earlier writers, and con- 

 firmation has since been given by Woodward (39), Mont- 

 gomery (31), Hoiiman (10) and Blatchford (2). Jutson (14) 

 inclined to the opinion that the old plated was an uplifted 

 peneplain, and this idea is adopted by Gregory (5) and by 

 Wcolnoug-h (44). Jutson (14) shows that the new plateau 

 is an eixample of levelling without base-levelling. Jutson 

 (14) follows an earlier publication by Gregory in regarding 

 most of Western Australia as being a very old land surface : 

 but Montgomery (31) considers much of the country has been 

 sea-submerged within comparatively recent times. Jutson 

 (14) considers that planation of the old plateau as a low 

 plain was pre-Pleistccene and }X)st -Jurassic, probably post- 

 Cretaceous (probably in early or middle Tertiary), and that 

 its uplift was probably in early or late Pliocene. Gregory 

 (5, 6) regards the uplift as Miocene or post-Miocene. 

 Woolnough (44) places the date of the close of the main pene- 

 planaticn at least as eld as Pliocene, with a strong probability 

 that it may be older still. Jutson and Simpson (29) have 

 suggested that the marine Plantagenet beds at Albany are 

 probably Miocene, so that the uplift there is Miocene or post- 

 Miocene. Mcntgcmery (31) thinks that the old plateau may 

 >e a marine plain. 



(h) The " /)/>/ " Lukes. — Jutson (14, 15, and 18) suggested 

 a twofold classification into deflation lakes and deformation 

 lakes, following Woodward (39 and earlier) as to the former. 

 Gregory (4), independently of^Gibson. who had previously put 

 forward a similar idea, suggested that the lakes were remains 

 of old Tertiary rivers, dammed up by wind-driven sands. 

 Montgomery (31 and 32 and earlier publications) regards the 

 lakes as remnants of shallow marine seas. Honman (10) 

 agrees with Gregory, but with modifications (9 and 11). 

 Taylor (38) inclines to the idea of the old Tertiary liver 

 system, but suggests that warping and block-faulting may 

 have aided in the formation of the lake basin?. 



The theory of the migration of the hikes was brought 

 forward by Jutson (14, 15, 18, 19), who pointed out the 

 frequently-occurring rock floors and rock cliffs on one side, 

 and wind-blown sands on the other. Blatchford (2) and 

 Honman (9, 11) adopt this theory. Jutson (18) has suggested 

 that a whole topographic system is migrating westwards. 



Montgomery (31, 32) considers that there were former 

 (jrenter lakes. Jutson (14, 15) suggests that while such 

 proha.bly occurred, the migration oi a lake might, in seme 

 instances, cause the appearance of a former greater lake 

 Honman (7) has suggested a former larger lake in the area 

 between Kalgfcorlie and Coolgardie. 



