 A band of Middle Devonian limestone runs west to east from Cremyll to Plymstock including the Hoe . Local limestone may be seen in numerous buildings , walls and pavements throughout Plymouth . To the north and north east of the city is the granite mass of Dartmoor ; the granite was mined and exported via Plymouth . Rocks brought down the Tamar from Dartmoor include ores containing tin , copper , tungsten , lead and other minerals . There is evidence that the middle Devonian limestone belt at the south edge of Plymouth and in Plymstock was quarried at West Hoe , Cattedown and Radford . 
