NEW YORK (Reuters) - The Toronto Stock Exchange's S&P/TSX fell 127.53 points, or 0.83 percent, to 15,285.17.
Leading the index were West Fraser Timber Co Ltd , up 6.5 percent, Alamos Gold Inc , up 6.1 percent, and B2Gold Corp , higher by 3.8 percent.
Lagging shares were Aurora Cannabis Inc , down 11.7 percent, Trican Well Service Ltd, down 7.6 percent, and Crescent Point Energy Corp, lower by 7.2 percent.
On the TSX 89 issues rose and 154 fell as a 0.6-to-1 ratio favored decliners. There were 1 new highs and 37 new lows, with total volume of 346.2 million shares.
The most heavily traded shares by volume were Aurora Cannabis Inc , Aphria Inc and Bombardier Inc.
The TSX's energy group fell 4.18 points, or 2.38 percent, while the financials sector slipped 0.14 points, or 0.05 percent.
West Texas Intermediate crude futures fell 4.44 percent, or $3.08, to $66.28 a barrel. Brent crude fell 4.37 percent, or $3.49, to $76.34 [O/R]
The TSX is off 5.7 percent for the year.
(Reporting by Lewis Krauskopf)