176 GLACIAL ACTION IN AUSTRALASIA. 
radiation from which the ice flowed outwards. The northern 
portions of this extinct ice field give abundant evidence of the 
transporting agent having passed over the great granitic out- 
crops of the coast near Port Victor. Erratics exhibiting the 
lithological characteristics of the Port Victor granites were 
noted on Kangaroo Island, but these were mixed with other 
types which appeared different from those present in the 
northern part of the extinct glacial field. A more detailed in- 
vestigation of this subject, and comparison with the granitic 
outcrops of the southern coast of Kangaroo Island, may bring 
to hght evidences which were not apparent to us during a few 
days of hasty travel under very trying climatic conditions. 
The inclusion of Kangaroo Island within the region affected by 
a past ice age, reveals the enormous extent of the extinct glacial 
area in South Australia. The glacial field can now be roughly 
described as forming an obtuse isosceles triangle, having a base 
of 70 miles in an east and west direction from the Hindmarsh 
Valley to Smith’s Bay, with its apex at Hallet’s Cove, 40 miles 
to the north. This forms the largest area comprehended in any 
one extinct glacial field known in Australia, and it is improbable 
that the extent of the field has even yet been fully defined. 
