Organism identification, what is this?

Im trying to find out what this is, see image below.

Im thinking these are either some insect eggs or some sort of mosslike plant.
The substance is stuck to a steel pillar, outside, about 5 feet above the ground.
The substance is found in the Netherlands in a wet meadow area.

The substance has multiple tiny cells or eggs, seems to be only 1 layer thick and has a soft/smooth feel to it.

Excuse me for the bad picture, my camera would not focus better because of the reflective surface of the pillar.