By Al Novack

PHILADELPHIA (CBS) – Authorities in Lower Merion say a medical examiner has been called to a riverside park where a truck plunged into the river.

Emergency dispatchers say the Mazda went into the Schuylkill River at Flat Rock Park in Gladwyne shortly after 7 a.m. Sunday. A witness reported the incident to police.

Rescue crews arrived, and they were able to remove a woman from the sinking vehicle. The woman was pronounced dead at the scene. The mini-van was retrieved from the river, and the deceased woman is believed to have been the only occupant of the vehicle.

The cause and manner of death are still under investigation. The identity of the woman, believed to be in her forties, is being withheld until next of kin can be notified.

A firefighter was also taken to Bryn Mawr Hospital for treatment of a minor injury to his finger.