George Mosman arrived on the Civilian with his twin brother Archibald Mosman in August 1828.
This land on the Williams River was a grant originally located to Adam Smyth and later purchased by George Mossman. It was known as Burroull.
DIARY OF GEORGE MOSMAN
The following are extracts from an old diary kept by Mr. George Mosman, manager of Burroull, Seaham, Williams River in 1839:
January 2 - Dr. Sloan here being his fifth visit to Mr. Mosman during his late illness.
January 3 - Heavy hail storm destroyed tobacco and other crops. Sent Mr. Archibald Mosman's horse 'Punch to Sydney by steamer Sophia Jane
January 3 - Mr. William Caswell at dinner and getting two ponies shod.
January 5 - Being a wet day all hands planting tobacco.
January 7 - Still planting tobacco
January 9 - Threshing wheat
January 12 - Mr. Hook here all night and left this morning for Sydney
January 13 - Mr. Mosman and Mr. Gilchrist rode to Mr. Nowlan's station
January 15 - Mr. Gilchrist at Maitland cashing order for Mr. Mosman and sundries
January 22 - Mr. Broughton arrived here from Sydney. Sent Laidlaw to Raymond Terrace with the boat for goods
January 27 - Mr. Mosman and Mr. James Gilchrist rode by Mr. Holme's property, crossed the falls and returned on the eastern side of the river
January 28 - Engaged all day branding calves
January 29 - Engaged all day branding calves
January 30 - Mr. Carmichael called to get a plough repaired which was granted. Received sundry goods form Sydney by the steamer Jane Williams
February 2 - Mr. Mosman left for Sydney by steamer from Raymond Terrace. Mr. Broughton returned from Dungog on his way to Sydney
February 5 - Shipped sundries to Sydney by Jane Williams. Mr. Kelso and McLeod here from Maitland
February 12 - Mr. W. Windeyer at breakfast, having come from Clarence town to meet his father. Captain Farmer's servant here from Sydney with horse
February 15 - Received letter from Mr. Mosman from Sydney directing me to send to Raymond Terrace for four bulls. Sent Laidlaw to Raymond Terrace with the boat for Mr. Mosman. Mr. Broughton and Colonel Snodgrass here from Dungog. Laidlaw and George at Raymond Terrace with the boat to meet Mr. Mosman but the steamer did not come in.
February 23 - Mr. McLean came here from Maitland
February 26 - Messrs. Windeyers here all night
March 1 - Captain Farmer here from Sydney. Mr. Mosman, Captain Farmer and James Gilchrist went to Maitland sales.
March 8 - Messrs G. and A. Mosman, Mr Alexander, Captain Farmer and Mr. Windeyer and Mr. Henderson returned from the Maitland sales and stayed the night. Branded horses purchased at Maitland sales. Mr. Alexander bought roan pony, Pedlar, and left with Mr. A. Mosman for Sydney
March 16 - Messrs McLean and Maister here from Maitland. Purchased all Mr. McLean's cattle at 3 pound per head.
Sold Mr. Caswell a second hand tanner for 13 to be taken out in cows at 5 pounds each
Mr. McLean left for Maitland and Mr. Maiston for Port Stephens
Mr. Caswell at dinner complaining greatly of want of water
Mr. Lord's man took away the 3 rams.
Mr. Broughton left with Mr. McLean's horses for the Upper Williams
Captain Farmer left for Sydney by the Green Hills with Mr. A. Mosman's horse Punch
Mr. McLean and stockmen went to Limeburner's Creek to look for horses.
Mr. Maister here from Port Stephens
Loaned large boat to Mr. Caswell to take wheat to Green Hills Mr. Caswell here all night
Mr. Jamison called on his way from Dungog
Mr. Hayle went with stockman to Mr. Hook's to look for working bullocks
Mr. John Gilchrist arrived from Sydney
Bushrangers supposed to be about
Mr. Mosman, Mr. John Gilchrist, Mr. Harper and Mr. Harvie left for Maitland
The missing English bull brought home by Mr. Caswell's son
Mr. John Gilchrist and Mr. Hooper left for Sydney by the boat but were too late for the steamer and had to return.
Commenced in growing tobacco seed in the bush paddock
Mr. Carmichael called to inform us that Lady Franklin wanted to cross at out punt on her way to Port Stephens.
Mr. Turner and Mr. Mitchell here all night
Mr. John Meskell made under overseer
Mr. Parkinson and Mr. McLeod came here.
All hands within doors on account of wet day.
Mr. Mosman returned from Sydney with Mr. Alexander and Mr. A. Mosman's horses
Took the level of swamp at American fence and depth of river bank
Assigned boys commenced to make up tobacco in their spare time at 3d per lb in 1oz figs
Champion at Raymond Terrace with letter and saddle for Mr. McLean
Sent to Green Hills to meet horse Prince George from Sydney
Mr Caswell called
Mr. Holmes passed
Sent Champion to Mr. Holmes for some fruit trees
Lent Mr. Caswell small boat
Mr. Hobler and Mr. Reid here all night
Mr. and Mrs. Carmichael called
Champion left for Maitland with three Hereford bulls and Mr. McLean's two working bullocks Champion returned from Maitland with two of the English bulls which were not sold
Major Johnston and the Rev. Ross called
Mr. Mosman and Mr. John Gilchrist of Sydney called on Mr. Warren at Brandon
Mr. John Gilchrist and Mr. Hobler came from Maitland
Captain Dun called and took the blacksmith to look at a sick mare
Mr. Rodgers, surveyor called for the loan of a measuring chain and remained the night
Rev. Mr. Spencer here all night
According to the old diary in the year 1839 there were six hired servants and 29 assigned servants employed on the estate exclusive of the manager Mr. James Gilchrist. 
George Mossman out-lived his brother Archibald by five years. He died on 5th September 1868 aged 68.
Select here to find some of the convicts assigned to George Mossman at his Williams River estate.
NOTES AND LINKS
National Library of Australia - Digital Maps Collection
 Maitland Mercury 7 January 1933