Gardaí are continuing to search an area where human remains were discovered by workmen near Midleton.
It is understood that investigators believe the skull has been there for many years.
Workers discovered the remains at around 4.30pm on Tuesday while clearing an area around Roxborough, which is being developed into a greenway.
The route is part of the former Midleton to Youghal railway track.
Garda sealed off both sides of Shanty Path to allow investigators to carry out their work.
Workers wearing hi-visibility vests could be seen carrying out a fingertip search of a wide, cordoned-off area close to a forest.
Gardaí are searching for further remains which may be in the area.
Assistant state pathologist Margaret Bolster was to visit the scene yesterday.
In a statement gardaí said: "Gardaí are investigating the discovery of suspected skeletal remains following an excavation that was taking place in Roxborough near Midleton in Co Cork at approximately 4.30pm on Tuesday.
"Gardai have since sealed off the area to allow for a technical examination which is taking place on Wednesday.
"The coroner has been notified and the state pathologist has been requested to attend the scene.
"The outcome of the examinations will determine the course of the investigation."