I was looking over some old Ancestry.com message boards and came across your query regarding Leornard Causley. I don't know much about him, but I believe his father, Silas Causley, was my grgrgrandfather's brother. My ancestor is Francois Xavier Cazalet (Frank Causley)....
I guess the brothers were Leon (Leo) Cyril, Silas, William, Richmond, Frank, and sister Phillis. My Frank's spouse was Mary Henderson. They had my grgrandmother, Jennie Causley.

I believe the genealogy goes like this:

Pierre Casselet (Cazelaist) etc. m. Marguerite Lasalle
child: Peter

Peter Casselay (Casselet) b. Millau , Rodez, France (Languedoc area)
m Marie Angelica Dupre dit Rochefort b 9 march 1741 (her parents were Jean Baptiste Dupre dit Rochefort and Angelique Dubois) m. 6 oct 1760 terrebonne,quebec.
children: Ignatius

Ignatius Casselay b Detroit, Mi. or Montreal m. Mary Angelica Huyet dit Champagne b. 1 jul 1780 in fox creek, mi (now gross pointe) d. 15 dec 1846 in Sandwich Ont. (parents Peter Huyet dit Champagne and Regina Christina Tremblay) (she reportedly could speak fluent Ojibwe, language of the Chippewa... m. 22 oct 1799 in Detroit. mi.
children: Ignatius, Joseph Solomon, Mary, Peter, Angelica, Gabrial, Edward, James, Cecilia, Peter and Vincent....

Ignatius Casselay m. Felicity LaForge (daughter of Louis Solomon David LaForge)
children Francois, Leon, Cyril, Silas, William, RIchmond and Phillis

etc. etc. etc.

Does this sound familiar?
thank you