On 1 November 1755 at 09:40 the Lisbon earthquake caused a tsunami to strike the Cornish coast at around 14:00. The epicentre was approximately off Cape St Vincent on the Portuguese coast, over south west of the Lizard. At St Michael's Mount, the sea rose suddenly and then retired, ten minutes later it rose very rapidly, then ebbed equally rapidly, and continued to rise and fall for five hours. The sea rose in Penzance and at Newlyn. The same effect was reported at St Ives and Hayle. The 18th-century French writer, Arnold Boscowitz, claimed that "great loss of life and property occurred upon the coasts of Cornwall".