Carrie, I don't believe your David Shanks is the same person discussed here on this posting. I think maybe he was from Scotland/Ireland and landed in Quebec via New York.
The Col Shanks of Missouri Civil war fame was born in Kentucky, never married, and ends up in Wyoming. He died in either Laramie or Denver in the early 1870s.
Sadly some of the contributors to this 2007 thread are no longer with us. Glad you found us though!