SAN FRANCISCO, Aug 31 (Reuters) -
* The Toronto Stock Exchange's S&P/TSX .GSPTSE fell 108.67 points, or 0.66 percent, to 16,262.88.
* Leading the index were Aphria Inc APH.TO , up 6.1 percent, Semafo Inc SMF.TO , up 4.5 percent, and Guyana Goldfields Inc GUY.TO , higher by 3.7 percent.
* Lagging shares were Maxar Technologies Ltd MAXR.TO , down 4.4 percent, ARC Resources Ltd ARX.TO , down 4.1 percent, and CES Energy Solutions Corp CEU.TO , lower by 3.6 percent.
* On the TSX 77 issues advanced and 165 declined as a 0.5-to-1 ratio favored decliners. There were 3 new highs and 8 new lows, with total volume of 212.5 million shares.
* The most heavily traded shares by volume were Aurora Cannabis Inc ACB.TO , Aphria Inc APH.TO and Canopy Growth Corp WEED.TO .
* The TSX's energy group .SPTTEN fell 2.90 points, or 1.44 percent, while the financials sector .SPTTFS slipped 2.03 points, or 0.65 percent.
* West Texas Intermediate crude futures CLc1 fell 0.46 percent, or $0.32, to $69.93 a barrel. Brent crude LCOc1 fell 0.41 percent, or $0.32, to $77.45 O/R
* The TSX is up 0.3 percent for the year.