British Atlas
The Atlas was first published in 1837 (Essex is dated 1835), and then several times to 1871 (or later), as Hobson's Fox Hunting Atlas (1850 to 1880), as Walker's Fox Hunting Atlas (up to 1895) and as Lett's Popular Atlas (1884 & 87). It was also dissected on cloth and sold folded up between boards.
Hundreds referenced to a table, plus listing parliamentary boroughs, places of election and polling places. Hundreds colour washed (but not edge-coloured), with Colchester, Harwich & Maldon Boroughs all blue-lined. Seven Polling Places in North, 7 in the South. Divisions thickly edge-coloured. Major roads have a thicker line on one side; all roads uncoloured.
"By J & C Walker" below the cartouche, but no imprint across base of the map.
Scale correct at 1+12 miles = 82.5mm, or 4.0 miles/inch; actual scale = 3.9 miles/inch, or 1:250,000.
The railways shown include the Witham to Braintree and Maldon lines (opened 1848), the Marks Tey to Sudbury (opened 1849) and Chapel to Halsted (opened 1860), but not shown are Manningtree to Harwich (opened 1854) or Barking to Tilbury to Mucking (also opened 1854).
There are quad black lines (without any red) from Chapel to Halstead (authorised 1856; opened 1860), from Sudbury to Clare and from Clare & Sudbury towards Bury St Edmonds (all 1847; 1865), from Manningtree to Harwich (1847; 1854), and from north Colchester to Hythe (1846; 1847).
There is a red line (no underlying black line) across northern Kent, labelled "Woolwich North and Kent Railway" (1837; 1849). The faint pecked black line from Romford to Thames Haven Docks has no red overlay.
The compass rose has moved from Hertfordshire into the North Sea, just west of the list of Polling Places. From the red lines, I estimate its selling date as being c.1849.