328 THE LAKE GEORGE SENKUNGSFELD, 



Creek is barely a mile long, yet descends nearly three hundred 

 feet. Its course is interrupted by falls 25 feet high, and finally 

 it emerges from a gorge, or miniature canon, with steep sides 

 200 feet high. Evidentl}'- it is a stream which has barely reached 

 the youthful stage. The hollows carved out of the slate bear 

 witness to the violence of the stream upon occasions, but for the 

 greater part of the year it dwindles to a succession of rocky pools. 



Travelling south, we arrive at a stream of some importance, 

 the Molonglo River, about 12 miles south of the lake. This cuts 

 across the Cullarin Range near Hoskin's Town (see Plate vii.). 

 Suspecting that this river might have participated in the abnor- 

 malities characteristic of the Lake George Basin, I wrote to Mr. 

 A. E. Tuckwell, of Hoskin's Town, who amply confirmed my 

 anticipations, as the following extract will show: — "The 

 Molonglo River leaves the flat country 5 miles to the west of 

 Hoskin's Town Public School, and flows through a 7iarrow gorge 

 bounded by hills, some of them apj)roaching mountains." 



An3^one who has enjoyed a trip up the Nepean from Penrith to 

 Mulgoa, will remember that, at the latter place, the river leaves 

 the plains and abruptly enters a steep gorge. The Nepean Gorge 

 is due to the river gradually eating doivn its bed as the Blue 

 Mountain scarp was elevated. This is the key to the Lake 

 George problem. The Molonglo River (see Plate viii., at the 

 lower rim of the model) has kept to its bed in spite of the fact 

 that its basin at one period of its existence experienced a differ- 

 ential movement, the upstream portion sinking with respect to 

 the lower. Subsequently (28th March, 1907) I visited the 

 Molonglo Water Gap and found that the river's course is con- 

 cordant with the above account. Immediately at the entrance 

 of tlie gorge, the slates and laminated quartzites are much 

 crumpled and overfolded. This is the only locality where I 

 observed such phenomena; the Silurian (?) strata, for the most 

 part, being folded on a large scale and not crumpled locally. 

 This local action occurring just at the plane where upthrow and 

 downthrow meet, would seem to suggest that some considerable 

 secondar}' folding has been supei imposed on the ancient Silurian 



