Who was the first to publish and publicise his view that a single continent existed about 300 million years ago?

Alfred Wegener (November 1, 1880 – November 1930) first piblicised the idea of a single continent in his book 'The Origin of Continents and Oceans' (Die Entstehung der Kontinente und Ozeane) first published in 1915. He postulated that all the continents had at one time formed a single supercontinent which he called the "Urkontinent", before later breaking up and drifting to their present locations.