Question: Walkley Heights, South Australia is located on land that formerly was a prison originally known as what?

Context paragraphs:
Dry Creek (South Australia): Dry Creek or Dry Creek Drain ( ) is a seasonal stream in South Australia which passes through the Adelaide suburbs of Modbury, Walkley Heights and Pooraka.  The nearby suburb of Dry Creek and Dry Creek railway station are named after the stream.

Adelaide Gaol: Adelaide Gaol was an Australian prison located in Thebarton, South Australia, Australia.  The gaol was the first permanent one in South Australia and operated from 1841 until 1988.  The Gaol is one of the two oldest buildings still standing in South Australia, the other being Government House which was built at the same time.  The prison is now a museum, tourist attraction and function centre.

The Heights Observatory: The Heights Observatory (also known as the Adelaide Observatory) is an Astronomical Observatory at The Heights School in Modbury Heights, Adelaide, South Australia.  A group of students known as the STAR Group learns astronomy at an advanced level, both in theory and practice.

Division of Makin: The Division of Makin is an electoral division for the Australian House of Representatives located in the northeastern suburbs of Adelaide.  The 130 km² seat covers an area from Little Para River and Gould Creek in the north-east to Grand Junction Road in the south and Port Wakefield Road in the west, including the suburbs of Banksia Park, Fairview Park, Golden Grove, Greenwith, Gulfview Heights, Ingle Farm, Mawson Lakes, Modbury, Para Hills, Para Vista, Pooraka, Redwood Park, Ridgehaven, Salisbury East, Salisbury Heights, St Agnes, Surrey Downs, Tea Tree Gully, Valley View, Vista, Walkley Heights, Wynn Vale, Yatala Vale, and parts of Gepps Cross and Hope Valley.

Protected areas of South Australia: Protected areas of South Australia consists of protected areas located within South Australia and its immediate onshore waters and which are managed by South Australian Government agencies.  As of June 2016, South Australia contains 353 separate protected areas declared under the "National Parks and Wildlife Act 1972", the "Crown Land Management Act 2009" and the "Wilderness Protection Act 1992" which have a total land area of 19,235,345 ha or 19.6% of the state’s area.

Salisbury Heights, South Australia: Salisbury Heights is a suburb located in the City of Salisbury, Adelaide, South Australia.  The upper section of Salisbury Heights was originally established as Castieu Estate in the 1970s by a private consortium.  The blocks of land in this area were typically much larger than surrounding suburbs with half acre blocks compared to the usual quarter acre block.  In April 2017, the Salisbury Heights section of Tea Tree Gully Council was renamed and amalgamated with nearby Greenwith.

Walkley Heights, South Australia: Walkley Heights is a suburb of Adelaide, South Australia.  The suburb is located on land formerly comprising the prison farm for Yatala Labour Prison, and includes fifty-five hectares of land formerly owned by R. M. Williams which was compulsorily acquired during the time of former State Premier Sir Thomas Playford.  The suburb (and one adjacent main road) is named after John Walkley, an early pioneer in South Australia

Cobbler Creek Recreation Park: Cobbler Creek Recreation Park is a 266 ha protected area located in South Australia about 19 km north of the Adelaide city centre in the suburb of Gulfview Heights.  Originally part of the lands of the Kaurna aboriginal people, it was farmed from European settlement of South Australia until the declaration of the park in 1989.

Electoral district of Playford: Playford is an electoral district of the House of Assembly in the Australian state of South Australia.  Named after the long serving South Australian premier Tom Playford, it is a 22.7 km² urban electorate in Adelaide's north, taking in the suburbs of Ingle Farm, Para Hills West and Walkley Heights as well as parts of Gepps Cross, Gulfview Heights, Northfield, Para Hills, Para Vista, Pooraka and Valley View.

Yatala Labour Prison: Yatala Labour Prison is a high-security men's prison located in the north-eastern part of the northern suburb Northfield in Adelaide, South Australia, Australia.  It was built in 1854 to enable prisoners to work at the creek, quarrying rock for roads and construction.  Originally known as "The Stockade" it acquired its current name from a local Aboriginal word.

Supporting paragraphs: Walkley Heights, South Australia Yatala Labour Prison
Answer: The Stockade