Joe,
If you have double set triggers, I'm guessing they need adjustment.  If you don't have those instructions from the manufacturer of your rifle, I can probably find some and post a link for you.

Never have heard it called the quarter cock notch...
CM

Joe,
For now, we'll say that your Palmetto and my Pedersoli use the same trigger design.  It should be true...let's assume that it is.

In that case you can find a .pdf file which has a set trigger adjustment procedure (instructions on Page 4, and diagram on Page 5) at this link.
(You need to Login or Register to view media files and links)

The file generally covers most of the Pedersoli models, but there is a small amount of Sharps-specific information near the end that you may find interesting, as well.

I made the guess that you might have a trigger adjustment problem because maladjusted triggers can cause the hammer (lock) to act funny.
However, your use of the term 'quarter cock' still has me puzzled.
Does your rifle have three positions that the hammer can be set in (in addition to fully down) like quarter, half and full cock?

For information geared specifically toward your Palmetto product, you might have some luck by inquiring at their email address.
info@palmettoarms.com
CM