[4] In 1839, after a severe illness, Clarke left England for New South Wales, mainly with the object of benefiting by the sea voyage.

[4] He had been commissioned by some of his English colleagues to ascertain the extent and character of the carboniferous formation in New South Wales (Clarke's letter to Sydney Morning Herald, 18 February 1852).

Clarke described finding it both in the detrital deposits and in the quartz reefs west of the Blue Mountains, the same area where McBrien had found it, and he declared his belief in its abundance.

[4] Mr R Lowe, Lieutenant William Lawson, an unnamed convict (who was flogged for the discovery), Dr Johann Lhotsky, and "Count" Paul Strzelecki had also found gold in Australia before Clarke.

Early in 1844 he showed the governor of New South Wales, Sir George Gipps, some specimens of gold he had found.

[4] He finished the preparation of the fourth edition of his Remarks on the Sedimentary Formations of New South Wales on his eightieth birthday, and died a fortnight later on 16 June 1878.

He was buried in the St Thomas cemetery, the graveyard of the North Shore church he was rector of for many years; and his widow and some descendants and relatives are close by.

His works in geology included the field of palaeontology and his collections and receipt of fossil material formed the foundation of research on Australia's extinct flora and fauna.

The results of his contemporaries studies and descriptions of Australian palaeontology and geology were incorporated into his own publications, and he remained current with advances in these fields despite his remote location.