Surrey 321 for 7 (Burns 76, Smith 58, Sibley 53) lead Somerset 283 (Lammonby 76, Gregory 62, Clark 5-68) by 38 runs
Rory Burns was one of three Surrey half-centurions as the defending champions took a first-innings lead against visitors Somerset on day two at the Kia Oval.
The Brown Caps skipper struck 10 boundaries in a fluent 76, sharing a first-wicket stand of 129 with fellow former England opener
Dom Sibley (53), who passed 50 for the fifth time in six innings this season.
England wicketkeeper
Jamie Smith was the third to reach his half-ton with 58 as the hosts reached 321 for 7 at stumps.
Somerset's bowlers recovered from a morning where they bowled too full a length, skipper Lewis Gregory leading the way with three for 46, including a double strike with the second new ball, as four wicket fell in the final session
Having bowled out Somerset for 283 on the cusp of stumps on day one, Burns and Sibley enjoyed a morning of dominance as they begun Surrey's reply.
Save for the odd ball which bounced a little for those bowling from the Vauxhall End and the odd lbw shout, Burns moved serenely along, Somerset's bowlers guilty of straying onto the pads too often to feed his trademark shot through mid-wicket. In fact, anything pitched up was quickly seized on by the 34 year-old left-hander as he raced to 50 from 77 balls.
As ever Sibley's progress was sedate but rock solid, the pair reaching lunch one short of the century stand.
If anything, Burns looked even better post lunch, driving with authority to move into the 70s and he appeared destined for a century before Josh Davey produced the ball of the day to remove him.
Bowling around the wicket, Davey extracted bounce and while Burns did everything right, trying to drop his hands, the ball followed him and smacked off the top glove for Kasey Aldridge to pouch the catch at slip.
Ollie Pope didn't detain us for long, bowled by skipper Gregory trying to cut a ball too close to him, but Smith came out bristling with aggression and began with a flurry of boundaries.
Sibley, the rock around whom others express themselves became barnacle-like even by his standards, failing to hit a boundary after lunch.
He reached a fifth 50 in 151 balls, but even he ran out of patience, uncharacteristically charging England spinner Jack Leach and being beaten in the flight. His ugly wahoo failed to make contact and he'd have been stumped had the ball not cannoned into the stumps.
The deceleration was catching with Smith slowly grinding to a halt despite his continued best efforts to hit the cover off the ball. He too would make it to his half-century before his innings ended tamely a mis-timed pull off Aldridge only travelling as far as Gregory at mid-on.
By this stage Ben Foakes was in flow, the diminutive wicketkeeper employing his wristy shots to good effect, sending successive deliveries from Leach to the fence at point. However, with 50 in sight he was undone by a beauty from back of a length by Gregory with the second new ball which nipped between bat and pad to pluck out the off-stump.
There was further reward for Gregory when Ryan Patel fell cheaply to a superbly judged tumbling catch at long-leg by Leach and Jordan Clark edged behind before the close to limit the home side's advantage.