Rewcastle,
For the short answer read below the line
Today's fairly young town of Blyth, developed, straddling the boundary between the parishes of Earsdon and Horton.
The "townships" of Horton Parish were West Hartford, East Hartford, Horton itself, Bebside and Cowpen, the most easterly one.
So the north and west of Blyth town lay in the Township of Cowpen, in the Parish of Horton. The south and east of Blyth lay in the Township of Newsham
( later name-changed to Newsham and South Blyth), within the Parish of Earsdon.
The old parishes boundary today is marked by the route of the old Plessey Wagonway-Plessey Road, then a sharp left turn onto UNION Street, meeting the River Blyth adjacent to where old gasometer was.
So places such as Post Office, Police Station, Ministry of Labour, Star & Garter, South Harbour, Blyth Beach, Links Cemetery and South Newsham would have lain in the Newsham/South Blyth Township of Earsdon Parish.
Cowpen Quay, Hodgson's Mill, North Pit and South Pit, Keelmans Row, shipyards, etc., lay in Cowpen township, of Horton Parish.
Which side of the "divide" determined where one was baptised,married or buried. Horton or Earsdon !
As Blyth quickly developed the two mother parishes built two "chapels of ease" for the benefit of their Blyth worshippers. Firstly St, Cuthberts, out of St Alban's, Earsdon, then St Mary's in the market place, out of St Mary the Virgin, Horton. Both these satellites eventually became independent parishes.
The "Cowpen" bit of Blyth and the "South Blyth&Newsham" bit were both separate Urban Districts, until they amalgamated in 1907, under Blyth UDC.
One of the problems they tackled was renaming streets with duplicated names..e.g. Wellington St, Market St, Croft St, Taylor St.
In 1901 census the Cowpen Township had 17,879 inhabitants, the N&SB Township had 5472.
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So in summary South Blyth was the southern and eastern of today's of Blyth, including South Newsham. The boundary of this township with Earsdon's township of Seaton Delaval was marked by Maggie's/Meggies Burn
Stop me somebody.
My main source is the "EARSDON and HORTON chapter of "A History of Northumberland" by HHE Craster.
Also old Trade Directories and a series of articles by roving reporters of the
NEWCASTLE WEEKLY CHRONICLE, published between Oct 1872 and Auig 1874, entitled "OUR COLLIERY VILLAGES"
I will have to access number 1 (Seghill) and number 121 (Backworth) to see if I can get any info on Morton Row... Newcastle Library
(article 100, 20th Sep 1873, was on Bebside, my birth-colliery.. reporter praised the cleaniness of our "privies and ashpits". They must have deteriorated by the time I came along in 1940s)
Michael Dixon