This particular brick oddity was salvaged from a house which was comprised solely "except this one" of unmarked Sydney dry-press bricks. A little research shows that Clayton and Co patented a brick press at the turn of the industrial revolution. The mechanised manufacturing process meant that brick production rates were greatly increased via the use of the specialised equipment.
Although it appears that the patented brick making machine was available for purchase in Australia, it is unclear whether any were actually sold, interestingly the brick appears to be comprised of material which is quite different to what would be expected of a brick made of local Sydney basin minerals.
Furthermore, the Clayton and Co brick making machine pressed their patent branding into one side but allowed for the owner to have their own brand or stamp placed on the opposing side. This brick not having been stamped with any markings on the reverse side suggests that it may have been imported to Australia - which actually happened more than you would imagine.
This is not the first curious brick uncovered from the demolition of an Australian home and it certainly wont be the last. In fact, Australia has a pretty wacky history with bricks and sometimes you simply have no idea what can be found in the walls of your typical home.
Given that one of these machines could produce more than 20,000 bricks in a single day, it remains a mystery as to where the others were utilised, or is this the only Clayton brick in Australia?