Set an unlikely 426 to win, the visitors were bowled out for just 127, with Somerset seamer Davey claiming 5-21
Taunton: Somerset 199 & 329 v Yorkshire 103-9 & 127-9 - Somerset win by 298 runs
Somerset's hopes of a first ever County Championship title were given a massive boost by a crushing 298-run victory over Yorkshire inside three days at the Cooper Associates County Ground, Taunton.
Set an unlikely 426 to win, the visitors were bowled out for just 127, with Will Fraine forced to bat at seven with a runner because of a knee problem and Ben Coad absent ill. Seamer Josh Davey claimed a career-best 5-21 from 11.2 overs.
Somerset had earlier built on their overnight second innings score of 269 for 5 before being dismissed for 329, George Bartlett making 47, Roelof van der Merwe 30 and Jamie Overton 18, including two towering sixes.
Keshav Maharaj returned 5-122 for match figures of 10-176 to become Yorkshire's leading Championship wicket-taker this season with 38 in only five appearances.
Somerset took 19 points from the game to Yorkshire's three and, with Essex battling to save their Championship game against Warwickshire, the Cider county look set to enter the last two games in pole position to win the competition.
The day began with Somerset looking to add quick runs. They lost Lewis Gregory (39), Bartlett and Dom Bess early on, but van der Merwe and Overton produced some lusty blows to take the lead beyond 400.
There was a moment of humour when van der Merwe pulled a ball towards the boundary, ran while following the path of the ball, and crashed into bowler Tim Bresnan in mid-pitch. Both sturdily-built men went down, but with no injury resulting from an incident inevitably bound for Twitter.

Davey's dismissal of Maharaj was the third wicket of his five-wicket haul
When van der Merwe fell to Maharaj, it meant the left-arm spinner had taken 31 wickets in six innings against Somerset. But the home side were buoyant over what looked sure to be a winning lead and soon set about finishing the match.
Adam Lyth was brilliantly caught low down at third slip by Overton off Davey with only seven on the board and Gary Balance fell in the final over before lunch, caught behind off a snorter from Overton.
Jonathan Tattersall had replaced Fraine as Lyth's opening partner and he was unbeaten on 14 at the interval, with Yorkshire 47 for 2.
That became 54 for 3 when Tattersall, on 20, was caught at first slip by James Hildreth looking to withdraw the bat from a delivery by Overton, who was working up good pace from the Somerset Pavilion End.
Harry Brook fell to a poor shot, bowled playing back to van der Merwe, and it was 94 for 5 when Bresnan, who had pulled a defiant six off Gregory, was run out by a direct hit from Bess at backward point after a mix-up with Tom Kohler-Cadmore over a single.
VISIT THE COUNTY HUB
Kohler-Cadmore edged another catch to Hildreth off the impressive Davey, who quickly followed up by pinning Maharaj leg-before for a duck and taking a return catch to remove the stricken Fraine.
Steve Patterson delayed the inevitable with a fighting 24 not out, but when Duanne Olivier was well caught by Bess over his shoulder at point off Davey, the Yorkshire innings ended before tea, with Coad unable to bat.
Davey, playing only his fourth Championship match of the season, returned match figures of 8-51. It was Yorkshire's fifth heaviest first-class defeat in terms of runs.
Somerset travel to the Ageas Bowl to face Hampshire next week before a potentially historic home game against Essex, starting on Monday September 23.
Courtesy of the ECB Reporters Network