A memorial cross to Ninnis and Mertz was erected on Azimuth Hill, to the northwest of the Main Hut, in November 1913. The cross was built by Francis Bickerton, apparently using remnant timber from the radio masts. The members were 1700 mm x 1700 mm, and stood to a height of 3.4 m with a crossbar that spanned 2.3 m.

A plaque was added to the cross, with an inscription by Hodgeman:

Erected to commemorate the supreme sacrifice made by Lieut. BES Ninnis, RF and Dr X Mertz in the cause of science AAE 1913 AJ Hodgeman

The cross has been blown off on numerous occasions. In 1931 it was reattached by BANZARE, in 1978 by ANARE, and a third time by the AAP Mawson’s Huts Foundation expedition in 1997/1998. The original plaque is now in the Library of the Australian Antarctic Division, Kingston, Tasmania. A replica is fixed in its place at Cape Denison.