Brown-out detection with an external clock ATmega1280

I'm using ATmega1280 with an external clock and I have some questions about the "safe operating area" for preventing EEPROM corruption with BOD.
The external clock is: Crystals 14.7456MHz 18pF HC49S SMD by CITIZEN, without clock division.
LINK to ATmega1280 datasheet

In the datasheet of ATmega1280 the flash and EEPROM unit gets two clock arrows as below: (page 39)
[ATTACH type="full"...

Brown-out detection with an external clock ATmega1280