Complex sentence: After exploring it, he named it for Sir Edward Hawke, First Lord of the Admiralty on October 15 1769, describing it as some 13 leagues (about 40 miles) across.
Split into simpler sentences: After exploring it, he named it for Sir Edward Hawke, First Lord of the Admiralty on October 15 1769. Describing it as some 13 leagues (about 40 miles) across.