England batsman Marcus Trescothick was in blistering form as he smashed a superb century to end Glamorgan's participation in the tournament at the fourth round stage.

The Somerset opener hit 20 fours in his 121, scored off only 83 balls, as he treated the Welsh attack with disdain.

He only gave one half chance, when a powerful drive crashed into Robert Croft's shin at short extra cover.

Peter Bowler was a virtual spectator at the other end during an opening stand of 143.

Trescothick, who is being considered for the job as England stand-in captain for the second Ashes Test at Lord's, never looked back after Steve Watkin conceded 25 off his first two overs.

Jamie Cox finished things off with three sixes in an unbeaten innings of 63 after Trescothick was finally bowled by Robert Croft.

Earlier, Glamorgan's Matthew Maynard made an unbeaten 93, including a six and five fours as he steered his side to an impressive total.

He steadied the ship with Michael Powell, who hit 52, in a fourth wicket stand of 93 after three Glamorgan wickets fell for 44.

But Maynard's efforts were eclipsed by Trescothick's destructive innings as Somerset reached their target in 41.4 overs.

Somerset: M E Trescothick, J Cox (Capt), M Burns, R J Turner (Wkt) K A Parsons, P D Bowler, I D Blackwell, K P Dutch, R L Johnson A R Caddick, P S Jones.

Glamorgan: I J Thomas, S P James (Capt), M P Maynard (Wkt), A Dale M J Powell, K Newell, R D B Croft, S D Thomas, D A Cosker O T Parkin, S L Watkin.