John Dewhurst was a Cotton weaver living at 57 Derby Street, Blackburn (and to confuse matters with exactly the same data at 69 Derby St, Blackburn) in the 1881 Census returns. There is a 2 year gap between the eldest child Mary Alice and John James and a 9 year gap between the birth of John James and his younger sister Ethelinda (Ethelander/Ethelrida in some documents). Birth Certificate for Ethelinda lists Mary Slater as her mother,I haven't obytained the other certificates, so given the gap it could be a second marriage or more likely a late pregnancy (at 39 yrs).
Johns birth place is listed as Billington, Lancs in the entry for 69 Derby St and Blackburn at 57 Derby St.
The 1881 Census also lists:- 34 Derby St = John (35) and Betty (36y) DEwhurst with 5year old George Thomas. 12 Derby St = Ellen Dewhurst (66y Widow) with Thomas (U 38y) Joseph (U 23y) and Ralph Thompson (7y) there are Thompson families at 8 & 6 Derby St.
If you can add any information to John & Mary or knows what happened to Mary Alice or John James or can tie in with the other Dewhursts on Derby Street (even though it is a Blackburn Name) it would help me.