When I was a boy of ten, living with my Grandmother Theo Conrad Mullen ( 1904 - 1964 )in Louisville, Jefferson County, Kentucky she had a great book 11" x 16" x 4" thick, published at no little expense by a relative and dedicated exclusively to the Shallcross Line.
It traced the family back to 1414 as evidenced by a bird with what looks like a four leafed clover in it's beak etched into an omphallus originally used to mark the boundaries of an ancestral estate.
At the time, as I recall there were well over 184 branches of the family, many of whom had their own spelling variation.
The book I feel was published in the era of 1827 - 1883 and is, alas, no longer extant.
Hopefully one among you has seen, or currently has access to this same volume.
If anyone can shed any light on this or related matters, Please- Contact me: