County Championship D2, Taunton (day two, close): Yorkshire 409-6; Somerset 275
Yorkshire established a huge advantage over Somerset thanks to an unbeaten 207 from captain Matt Wood.
Wood had been put in the shade by Stephen Fleming in an opening partnship of 165 in which the New Zealand skipper hammered a rapid 98.
Nixon McLean effected a middle-order collapse when he dismissed Yuvraj SIngh and RIchard Blakey cheaply in figures of 3-87.
But Wood refused to panic and eventually found an ally in Andy Gray, who hit 44 not out down at number eight in an unbeaten seventh-wicket partnership of 112.
Somerset: P D Bowler, M J Wood, J D C Bryant, J Cox, M Burns (Capt), I D Blackwell, R J Turner (Wkt), A W Laraman, N A M McLean, P S Jones, S R G Francis.
Yorkshire: M J Wood (Capt), S P Fleming, C White, M J Lumb, Yuvraj Singh, R J Blakey, S M Guy (Wkt), A K D Gray, C E W Silverwood, R J Sidebottom, S P Kirby.