A 1906 guide to resorts in the Canadian Rockies describes Lake O'Hara, in the next valley west of Lake Louise and across the Continental Divide. It goes on, A couple of miles away is McArthur's Lake, a sapphire gem, located above the tree line, and with a huge glacier, fed on the precipitous heights of Mount Biddle, terminating in the water, where it breaks off in huge icebergs.