Ah, now I understand the confusion, pigeon quoted zlymex's post which also contained a (different) schematic.
As Cerebus and iromero point out there needs to be a DC feedback path. The output of the opamp is driving the 'ground' via the 100R to buffer it from capacitance involved. The opamp is sensing the 'ground' voltage via the 1M to establish the DC return path of the voltage follower. The 10n capacitor provides local HF feedback around the opamp for stability.
I found these component values to be needed for stability
in my implementation. The LMC662 was 'twitchy' in driving the ground (low frequency instability). I suspect that it is because 'ground' in my case was the copper groundplane of the board. At that point I didn't want to significantly change the layout so I went with stabilisation values that worked solidly.
The circuit is however a simple voltage follower at DC, with the output at half-rail with fine trim to cancel the opamp input offset voltages. The 1M resistor also matches the one on the inverting input of the 'measuring' opamp which hopefully also minimises bias current offsets (this does seem to work as output offset at the uV level is maintained pretty well over normal ambient variations).
P.S. @bdivi, I hadn't noticed your post with the implementation of the "Gyro picometer" (undeserved fame at last!
![Embarrassed :-[](https://www.eevblog.com/forum/Smileys/default/embarrassed.gif)
). It looks a neat implementation and it's good to see that it performs so well.