Bronze Age Britain had large reserves of tin from mining in Cornwall and Devon. Tin is necessary to smelt bronze. At that time the sea level was much lower, and so tin for export could be brought across the Solent at low tide on carts, or possibly on boats such as those found at Ferriby. A shortage of tin during the Bronze Age collapse and trade disruptions in the Mediterranean around 1300 BCE may have forced metalworkers to seek an alternative to bronze.