96 
The marine deposits at Lake Cowan show positively that ele- 
vation from probably a considerable depth below sea level up to 
about bOO'^' feet above il, has taken place at that point, and if Lake 
Cowan be admitted to l)e the residuum of a cut off arm of the sea. 
it is only reasonable to extend the same explanation to Lake 
Lefroy, Hannan’s Lake, Lake Yindarlgooda. and Lake Lepage, 
which are connected with one another hy plains into which the 
margins of the lakes merge imperceptibly, llannan's Lake how- 
ever, is at about the KHU) feet level. The ])lain country is trace- 
able on to the north almost continuously, though studded with fre- 
quent island-like grout)S of hills, to connect with Lakes Ballard, 
Barlee, Raeside, Carey, etc., right up to T.ake Way, the elevation of 
which is about feet according to Professor Gregory. The 
physiogra])hical features of the country round Lake Cowan are 
quite similar t{) those of the whole lake tract right up to Lake Way, 
and if physiographical evidence is of any value, the shaping of the 
land surface has been due to like agencies all the way. At Lake 
Cowan we have direct evidence that the lake was once an arm of 
the sea. and the conclusion seems irresistible that the marine inva- 
sion extended inland along the lake country to beyond Lake Way. 
Such an extension would bring it over all the Central and Eastern 
Goldfields, unless the relative levels of the different parts of the 
country have been altered unequally, of which no evidence has been 
brought forward as yet. though there is no inherent improbability 
that such may have been the case, and indeed there is a good deal 
of probability that it would be so. 
According to this theory the present sha])c of the land surface 
of the goldfields iq) to at least the 20()() feet level would mainly be 
that imi)ressed u|)on it during the re-emergence of the land and 
retreat of the sea. probably in Bost-'l'ertiary times, and in the 
writer’s opinion the whole of the characteristic features now visi- 
ble agree consistently \s’ith those which would be necessary conse- 
quences of such a history. 
It will be intere.sting to find how this theory will stand the test 
of the biological line of argument, for if it be correct there would 
undoubtedly be consecpicnces affecting the di.stribution of both plant 
and animal life. The theory would require that in Post-Tertiary 
times this State has been at times more or less of an Archipelago 
in a shallow sea. which would result almost inevitably in some 
amount of differential variation of l)oth the fauna and flora cut 
off on the islands, 'fhe result to be expected would be that we 
should have somewhat marked faunal and lioral provinces, difficult 
to account for if the land surface had been continuous for a very 
long sjiace of time. 'Phis interesting subject is beyond the scope 
of the present i)a])er, and is left to be dealt with by writers more 
conversant than the ])resent author with the botany and zoology of 
the State. 
*N’orseman Railway Station, 927 feet above the sea level. 
