Merthyr needed a coastal export point for its iron and Cardiff was the obvious choice being at the mouth of the River Taff .
The event that changed the face of coastal Glamorgan was the growth of the Merthyr iron industry .
Merthyr needed a coastal export point for Glamorgan 's iron and Cardiff was the obvious choice being at the mouth of the River Taff .
The event that changed the face of coastal Glamorgan was the growth of the Merthyr iron industry .