Yorkshire were subjected to a violent assault from Somerset at Scarborough yesterday - and the damage could have been much worse if they had not hit back to capture the last six wickets for only 46 runs.

Somerset's 451 in 96.3 overs still gave them a healthy first innings lead of 155 and they were closing in on their first Championship win of the season when Yorkshire ended the day in disarray on 63 for three, still trailing by 92.

Centuries from Australia's captain Ricky Ponting and left-handed opener John Frances had Yorkshire rocking before they were floored by two explosive innings from Michael Burns and Ian Blackwell who both made it into the 70s.

Yet all was not gloom and doom because the 3,500 crowd responded generously to some well-flighted leg-break bowling from 18-year-old debutant Mark Lawson.

And a great cheer went up when Lawson finally struck by wrapping up the innings with consecutive balls, the first bowling Simon Francis and the next having Nixon McLean caught at long leg by Richard Dawson.

The second day started with Somerset on 58 for one and Yorkshire's bowling coach Steve Oldham doing square leg umpiring duties in the absence of Mark Benson who had returned home with an injured foot.

Oldham stayed in the middle for around 80 minutes until former Yorkshire batsman Richard Kettleborough, now on the reserve list of first class umpires, took over.

Ponting was in such a hurry that he added 50 to his overnight 15 while Francis was accumulating just six, and such progress was made against the pacemen that the pair soon overtook the previous highest second wicket stand against Yorkshire at Scarborough of 148 between Alan Jones and Graham Gooch for an International XI in 1975.

Ponting, batting with confidence and style, became the fifth Somerset batsman to complete a century on his Championship debut and the stand reached 197 in 45 overs when Ponting was out for 112 just before lunch. He got a leading edge on Dawson's arm ball and was well caught at the second attempt by Andrew Gale at silly mid-off.

Francis, who had shown his own hitting capabilities by driving Dawson for two big sixes in his first over, went to his century early in the afternoon but he then slashed at Chris Silverwood and was caught by Ismail Dawood for 109 from 188 deliveries with 11 fours and a six.

Somerset's really big guns were still waiting to be fired, however, and they were sounded off by Burns and Blackwell who made 113 together in 17 overs, Harvey coming in for some barracking from the crowd as loose legside deliveries were brayed for sixes by Blackwell.

Two of Blackwell's sixes cleared the ground and the powerful left-hander was in sight of the season's fastest century when he wafted Darren Lehmann to Dawson at mid-wicket and departed for 73 from 54 balls with four fours and six sixes.

Dawood pulled off a brilliant stumping to send back Burns for 74 with ten fours and a six, scooping the ball from the floor and knocking down the stumps with the batsman out of his crease, and although Somerset's tail did not wag their bowlers soon tightened the stranglehold.

Gale avoided bagging a pair on his Championship debut, but fell to a stunning catch at third slip by Keith Dutch off McLean who then had Michael Lumb gloving an intended hook to the wicketkeeper and when Anthony McGrath tamely drove Dutch to mid-on, Yorkshire were in trouble at 54-3.