39 The James and Mary's and Adjacent Channels as Surveyed in April 1857.
Scope & Content:
Scale One Thousand feet to an Inch. Joseph Obbard, River Surveyor, H.C.S.V. Cavery, off Calcutta, 6th May 1857. T. Black, Lithr:, 4 Waterloo Street, Calcutta.
40 The Mud Point And Auckland Channels, And Kedgeree Roads.
Scope & Content:
As surveyed in May 1857. Scale of a thousand Yards to an inch. Joseph Obbard, River Surveyor, H.C.S.V. Cavery, Diamond Harbour, 29th May 1857. T. Black, Lithr:, 4 Waterloo Street, Calcutta.
As surveyed in May and June 1857. Scale of a thousand Yards to an Inch. Joseph Obbard, River Surveyor, H.C.S.V. Cavery, Diamond Harbour, 14 th June 1857. T. Black, Lithr:, 4 Waterloo St., Calcutta.
As surveyed in October & November 1857. Scale of a thousand Yards to the Inch. Joseph Obbard, River Surveyor, H.C.S.V. Spy, 18th Novr. 1857. T. Black, Lithr:, 4 Waterloo St., Calcutta.
As surveyed in October 1857. Scale of a thousand Yards to the Inch. Joseph Obbard, River Surveyor, H.C.S.V. Spy, 18th Novr. 1857. T. Black, Lithr: 4 Waterloo Street, Calcutta. Manuscript additions by Barlow. Formerly numbered 4.
As surveyed in December 1857, & January & February 1858. Scale of a thosand Yards to the Inch. Joseph Obbard, River Surveyor, H.C.S.V. Spy, off Calcutta, 22d. Feby. 1858. T. Black, Lithr:, 4 Waterloo St., Calcutta. Annotated by Barlow.
45 The Rangafulla Channel as surveyed in May & June 1858.
Scope & Content:
Scale a thousand yards to the Inch. Joseph Obbard, River Surveyor, H.C.S.V. Spy, off Kedgeree, 7th June / 58. T. Black, Lithr: & Engr:, 4 Waterloo St., Calcutta.
As surveyed in September and October 1858. Scale a thousand Yards to an Inch. Joseph Obbard, River Surveyor, H.C.S.V. Spy, off Calcutta, 27th Octr. / 58. T. Black, Lithr:, 4 Waterloo St., Cal:.
As surveyed in October 1858. Scale a thousand Yards to an Inch. Joseph Obbard, River Surveyor, H.C.S.V. Spy, 27th Octr. 1858. T. Black, Chromo-lithr:, 4 Waterloo St., Calcutta.