Robert? Stevenson was appointed the first Protector in early 1837, but stayed in the job only a few weeks.  His successor Walter Bromley, a missionary with long experience in the Americas, took over until late 1837, but drowned in the Torrens.  
Chester Schultz has kindly contributed these transcripts. 
Dr. William Wyatt, the third Protector after Stephenson and Bromley, took up the job in late 1837, until mid-1839.    Alistair Crooks has kindly typed up Wyatt's report.

protector's correspondence, 1840 -  1913
        

Dr Moorhouse took over from Wyatt as Protector from 1839 to 1856;  Dr Walker took over from 1863 until his death in 1868;  Edward Hamilton took on the role from 1873 to 1908, followed by William South. 
These first eight files cover the letters of the S.A. Protector of Aborigines from 1840 through to 1913, a total of eight and a half thousand letters over 2,500 pages - the Indexes alone cover two hundred pages:
Small summary article here: 
Volume One:  1840 - 1857.  

From 1857 to 1863, there was no Protector, and so no 'Department'.   So the routine work  of provisioning ration depots was handled by clerks in the Crown Lands & Immigration Office.  Going through boxes and boxes of files, I just found a letter from Florence Nightingale, enquiring about Aboriginal children's health at Mission schools !  Wow !  You never know what you'll find.   
Volume Two:  1863-1866 
 Volume Three:  1866-1870
Volume Four: 1871-1879
Volume Five:  1879-1884
Volume Six:  1885-1891
Volume Seven:   1892-1906
Volume Eight:  1906-1913

index of aboriginal people named in the correspondence out: 

There are nearly fifteen hundred people mentioned here - perhaps some of your relations ?  Press here:

Register of letters to the S.A. Protector, 1866-1901:

The one-man 'Aborigines Department', i.e. the Protector, had to deal with a host of issues day-to-day.  During this period, he received thirteen thousand and a half letters and, from his letters OUT, one can see that he responded fairly promptly to them all.   
 

INDEX OF ABORIGINAL PEOPLE NAMED IN LETTERS IN: 

combined index of Aboriginal people named in the Protector's correspondence IN and Out. 

List of "half-castes" in South Australia in 1909

This term is now quite offensive, but the list of people, and where they were in 1909, might be valuable to many people today.  Check out the number of 'state children'.   

Index to issues of  land, boats and guns

In nineteenth century South Australia, Aboriginal people could apply for grants of land, i.e. 14-year leases up to 160 acres, renewable, and rent-free.   Some Aboriginal men took out extra leases, for which, like other people, they had to pay annual lease-fees. 

The Protector also allocated 15-ft boats, ‘canoes’, and fishing tackle (fishing lines, hooks and netting twine) to about a hundred people, sometimes to groups at particular places on the coast, but usually to individuals.  If the Aboriginal people involved were working, from about 1890, they were expected to pay half the cost of a boat.  Otherwise, the boats were provided free.   Repairs were paid for on the same basis. 

As well, guns were provided to Aboriginal people around the state on the same basis, cost-free for people who weren’t working, or able to work, and half-cost to working people.  In South Australia, Aboriginal people have always been able to purchase and use guns freely. 

Re-Thinking Aboriginal History   

This article tries to summarise observations on the content of the Protector's Letters.  
Re-Thinking Aboriginal History

COMBINED INDEX OF ALL ABORIGINAL PEOPLE INCLUDED IN THESE FILES
Just added - a complete, combined Index of all Aboriginal people named in all major files on this site - more than sixty pages, with references to more than two thousand people.