Geometrid Caterpillar?

Geometrid Caterpillar?

Observation - Geometrid Caterpillar?. Description: Found on bridge railing above freshwater with mature trees surrounding. Not sure if i disturbed the critter or whether it was dead but when i picked it up it had a silk thread coming from the mouth which was attached to the railing. Sorry little one x An

Found on bridge railing above freshwater with mature trees surrounding. Not sure if i disturbed the critter or whether it was dead but when i picked it up it had a silk thread coming from the mouth which was attached to the railing. Sorry little one x
Any ideas on whether it is what i think it is and what the behaviour was about would really be appreciated thank you :)