Though small in size, prime oil sketches by Group of Seven founder Lawren Harris have often proven mighty performers at auction. That truism is expected to be affirmed Tuesday evening in Toronto when a 26-by-35-centimetre Harris, called Algoma (Algoma Sketch 48), goes up for bidding at a live sale hosted by Consignor Canadian Fine Art. Little seen, as it's been quietly held by a Canadian-born collector in Canberra for the last 35 years, the autumn scene carries a presale estimate of $400,000 to $600,000. No one, however, is going to be the least surprised when it fetches more than that; the surprise will be how much more. The painting seemingly has everything going for it – rarity, good condition, the Harris "look," the right year (likely 1920, when Harris started the Group), the right locale (the North!) and the right history (as the preparatory sketch for at least three full-scale Harris canvases, including 1921's Island, MacCallum Lake, now in the Vancouver Art Gallery). The current owner, whose now-deceased father purchased the work in Toronto in 1940, reportedly decided to sell after reading reports last year of the hubbub surrounding The Idea of North, the acclaimed Harris survey curated by Steve Martin. The exhibition, which opened at the Hammer Museum in Los Angeles last October, is now at Boston's Museum of Fine Arts in advance of an appearance in July at the Art Gallery of Ontario.