
This pic was taken in George St looking South...it shows the first stage of the Sydney GPO under construction. If you zoom in you can see that on this side they're 4 blocks above the upper level windows...and about to start on the cornice. This pic appears to have been taken in 1870...just going on the SMH item I've linked to below, the cornice appears to have been completed in ca. September 1870...
This pic is from the SLNSW's collection...
trove.nla.gov.au/work/13253785 - Trove link to the pic at the SLNSW...
trove.nla.gov.au/work/231388762 - this slightly earlier NAA pic can be dated to 1870...over to the right, there's a poster up for the All England Pedestrians (professional runners) who visited NSW from ca. April-July 1870...
trove.nla.gov.au/work/231392167 - a much earlier stage of construction...
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trove.nla.gov.au/newspaper/article/13211984/1458948 - SMH, 23rd September, 1870... this item refers to a stone setting ceremony on the cornice...which then appears to have been either completed or nearing completion...my guess is that this is when the stone with the date '1870' was put in position...
'THE NEW POST OFFICE - Yesterday morning a number of gentlemen assembled at the new Post Office building, at the invitation of Mr. John Young, the contractor, to see one of the principal stones of the cornice placed in position in the George street front. Among the company were the Premier (the Hon. Charles Cowper, C.M.G.), the Treasurer (the Hon. Saul Samuel), Mr. Parkes, M.L.A., Mr. Wilson, M.L.A., the Mayor of Sydney, the Colonial Architect, several members of the Legislative Assembly, and members and officers of the Corporation of Sydney. The stone weighed nearly twelve tons ; and, such is the perfection of the appliances at hand, that the contractor was enabled to raise it to a height of 84 foot in exactly five minutes. The visitors spent some time in the examination of the building, and great admiration was expressed at the handsome appearance of the polished granite columns, of which there are thirty-six in the building.'
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The first stage of the Sydney GPO was built between 1866-74 (from foundations to internal fit-out) ; Architect: James Barnet (the Colonial Architect); Contractors: Aaron Loveridge (foundations) and John Young (superstructure)...
trove.nla.gov.au/newspaper/article/13129964 - SMH, 21st April, 1866… ‘City Improvements’ 'The only work of any magnitude going forward in the city for the Government is the General Post Office, in George-street, the massive foundations of which are now being rapidly put in by the contractor, Mr Loveridge.'
trove.nla.gov.au/newspaper/article/13180633 - SMH 29th January, 1869… ‘The New General Post Office Sydney’ …per this item the foundations had been completed a year or so earlier, and the construction of the superstructure was in progress…
trove.nla.gov.au/newspaper/article/13188379 - SMH, 2nd April, 1869 … ‘The New Post Office’...report on the Duke of Edinburgh laying the keystone of the central arch of the George St facade the previous day...
trove.nla.gov.au/newspaper/article/70458934 - the Australian Town & Country Journal, 16th April, 1870...description of the GPO, then under construction...no specific details re the state of construction at that point...
trove.nla.gov.au/newspaper/article/162482873 - the Sydney Mail, 5th September, 1874… ‘Opening of the New Post Office’…report on the opening of the new GPO...