I am researching into a family, which at various times during the late 19th century and early 20th century knew themselves as
Dennison Atkins Dennison-Atkins
with the obvious variations as
Denison Atkins Denison-Atkins
Henry Atkins (b. c1850 in Norfolk UK) married Mary Ann Aviolet in the 1870s, possibly in Pennsylvania. They had children Emma, Henry William and Archibald James in the 1870s and 1880s. Emma was apparently born in Pennsylvania but the two sons were born in Portsmouth UK.
Henry William married Ida Beatrice Bufton in 1905.
Archibald James married Adeline Messenger in 1912 in south London UK. Their son was called Reginald Francis.
I have no idea why their family name varied with time or where the Dennison connection arose from.