A younger brother of Charles Theodore Forbes, Alfred Theodore Forbes, was born in Leek Staffs in Dec Q 1842, and his christening details show that he was baptised in Grindon, Staffs, on 29 Jan 1843, father Edward Forbes/mother Isabel.

I can't find Charles, Alfred or their parents in 1851 or 1861. Charles and Alfred both married in Australia in the 1860s (this info from someone's ancestry tree).

I believe that Charles and Alfred were half brothers of Edward Forbes b 1815, the naturalist. In the Wikipedia entry for Edward b 1815, there's this reference:

"Towards the end of the year 1842 Forbes, whom family misfortunes had now thrown upon his own resources, sought and obtained the curatorship of the museum of the Geological Society of London. "

Jean C