Steven Croft hit an unbeaten 113 to lead defending champions Lancashire to 363 for four on the opening day of their LV= County Championship Division One match against Somerset at Taunton.
Croft, whose knock came from 185 balls and included 11 fours and two sixes, enjoyed a fourth-wicket stand of 208 with South African Ashwell Prince (96) as the visitors dominated the opening day.
Karl Brown made 50 and Stephen Moore 47.
England batsmen Ian Bell and Jonathan Trott enjoyed contrasting fortunes as Warwickshire reached 281 for five against Sussex at Hove.
Bell, who has struggled for runs with England during the series against Pakistan and Sri Lanka and also since his return to domestic action, fell for a duck, bowled by James Anyon after facing seven balls.
Bell's dismissal saw Warwickshire struggling on 13 for two after also losing opener William Porterfield for eight, but Trott stuck an unbeaten 132 and Varun Chopra made 105, the pair putting on 219 for the third wicket, as the visitors recovered in style.
Richard Jones took four wickets and Aneesh Kapil three as Worcestershire dismissed Nottinghamshire for 243 at New Road.
Alex Hales top-scored for Nottinghamshire with 49, while Worcestershire were five without loss at the close.
No play was possible on the first day of Surrey's clash with Durham at the Kia Oval because of rain.
In Division Two, Matt Coles took four wickets as Kent dismissed Yorkshire for 247 at Canterbury, with no-one scoring more than 38.
The hosts were four without loss in reply.
Leicestershire were 159 for six against Hampshire at the Rose Bowl, thanks to 68 from Greg Smith.
The remaining Division Two matches between Essex and Northamptonshire and Gloucestershire against Glamorgan were washed out.