Hi,
I think I have a possible connection now after some digging around.
From the Will of Thomas Jerramthere are the following names and relationships. Thomas died in Q1 1852 between 23rd Jan and 8th March 1852.From the 1851 census he was born in Blidworth Notts around 1778/9.
Amelia (AKA Emily) Jerram - Daughter
George Turner Jerram - Son
Harriet - Wife
John Jerram - Nephew (Tea Dealer)
Mary Orton (nee Jerram) married to Dr Henry Orton (Surgeon) see :
http://www.rootschat.com/links/08ea(This family were in Canada by 1834).
At his death Thomas left property in both Cheltenham and Beeston Nottingham.
I think it very likely that Harriet, who is a several years younger than Thomas, is a later mariage and the the mother of Mary & George is Mary Turner married in Leeds in 1802 although there is a possibility that it could be a Sarah Turner.
Thomas appears to have had at least four siblings all born in Blidworth
John 1768
Charles 1770
William 1774
Samuel 1776
Thomas 20/11/1778
all born to Charles Jerram and Mary (Knutter ?) married 23rd/2/1768 in Blidworth.
It seems likely that Charles was baptised in Sawley and Long Eaton 17/10/1734, born to John and Mary Jerrom. If this is correct then Charles is an older brother to your James born in 1745.
If you think this is likely correct then I suggest you check out your Canadian cousins.
I hope this is helpful to you both.
Best regards - Mark