34 THE VICTORIAN NATURALIST. 



dam, its structure, as well as the general character of Lake Nigo- 

 thoruk strongly suggest to him a moraine blocking up the valley. 

 To positively determine the real nature and origin of the lake 

 will require a detailed geological examination of the locality,. 

 which at present it has not been possible to make. 



Dr. Dendy explains matters as follows : — The upper part of the 

 Barrier (and Nigothoruk) Creek originally flowed in a continuous 

 stream down from the high plains through the valley or basin where 

 the lake now is, but where there was then none, and then through 

 a deep and at first narrow gorge bounded by two high cliffs, one 

 on the Mount Wellington side and one on the other side, then 

 onwards along its present course. The cliffs on either side of the 

 narrow gorge weathered year by year ; the frosts and heavy rains 

 detached great fragments, which rolled down into the gorge and 

 blocked it up. In this way the barrier was formed and the 

 valley below partially filled with great rocks. The cliff on the side 

 of the gorge away from Mount Wellington weathered away com- 

 pletely, the process being very probably aided by great landslips 

 from time to time; on the Wellington side a great part of the 

 cliff still remains. In this way the waters of the river were 

 dammed back by a great barrier of rocks, and formed the lake, 

 and the stream was divided into two parts — the Nigothoruk Creek, 

 flowing down into the lake, and the Barrier Creek, which flows out 

 through the Valley of Destruction. Apparently these two parts 

 are now disconnected, but only apparently, for the water flows 

 through the rocky barrier, and comes out again below it. 



To Mr. Lucas's mind there are difficulties in both these 

 explanations. The phenomenon is unique, and required a very 

 precise and peculiar combination of conditions and forces to 

 produce it. If it be a glacier lake there surely should be others 

 in the district, and especially among the higher mountain ranges 

 to the north-east. No such lakes exist. The moraine, if a glacier 

 moraine, is most remarkable. The loose rocks are now angular, 

 which implies comparatively recent weathering ; they all seem to 

 be of the same nature as one another and as the bed rock of 

 Dendy's Heights and the rocks thought to be in situ in the central 

 ridge. The group of rocks particularly described above showed 

 plainly the way in which the rocks are still weathering. The land- 

 slip theory seems at first to explain matters ; but, again, there are 

 many narrow gorges and steep opposing cliffs, yet no other land- 

 slip lake is known in Gippsland. The top of the Barrier is as flat 

 as that of a breakwater, and it is not easy to see how it could be 

 levelled so uniformly if it were a landslip. The water, too, would 

 find its way round a landslip, and soon construct a new channel, 

 especially if the debris were accumulated gradually. He rather 

 inclines to the view, then, that the water leaves the lake as it at first 

 left the river bed, by fissures along the joints of the irruptive 



