You can see kernel boot messages with the command
Boot-time messages that come after the kernel starts tend to go in /var/log/boot.log
You could also try pressing Scroll Lock and shift+PgUp and shift+PgDn to scroll back up; this will only work after the kernel has started and initialised the keyboard driver.
Edit: You may want to use
to be able to scroll through the output with the cursor keys. (Q to quit.)