Startup disk not correctly identified? I have a Mid-2010 4 core MacPro. I mainly run 10.6.8, as I have a large software investment I'm not ready to abandon. As part of my migration to the present day OS, I have multiple startup drives, 2 PCI based SSDs. 

When I am running 10.6.8 and attempt to reboot into 10.10, I see this;



Obviously not 10.10. So I attempt a boot and disc utility comes up offering the usual menu to restore the OS drive. When I quit the utility, I'm offered a choice of startup drives:



Now, the startup choices appear correctly, and boot me into 10.10. When running 10.10.2, I get a fast boot back to 10.6.8. 

As it stands, I need 2 boots to get into 10.10 when running 10.6.8 prior. Why does the system still see any remnant of Lion? 

Edit - perhaps the right question is - "Sagan SSD contains 10.10, why does this show as 10.7 when trying to boot into it while running 10.6.8?"

In response to the comment, diskutil list shows -



and it appears to me that when I try to boot Sagan SSD it's the recovery HD that tries to boot.
Did you try to press the "option" key during startup? This will prompt you to select the startup disk if several are available. Set the system to boot into the one you will boot into most often, and if you want to boot into the other, press "option" when you switch the Mac on and wait for the prompt.