Accessing system counter for ArduinoMega2560

Is there a way to access the ATmega2560's system count register where I can just read a clock value? I am trying to get a resolution higher than micros() can provide.

Something like SysTick on Arduino Due where issuing the command SysTick->VAL will give you the number of clock ticks as the counter keeps counting down from 83999 to 0 with each clock tick.
Any direction would be appreciated. Thanks!

Reference: http://forum.arduino.cc/index.php?topic=187148.0[1]