Jack Brooks took five Worcestershire wickets as Yorkshire guaranteed their Specsavers County Championship Division One status by claiming the two bowling points they needed.
The Tykes were safe when Somerset-bound Brooks trapped Ed Barnard leg before to leave the home side on 255 for six, and he ended the day with five for 83 from his 19 overs.
Daryl Mitchell's 127 and 60 from Moeen Ali helped the home side to 319 for eight at the close on day one at Worcester.
— Surrey Cricket (@surreycricket) September 24, 2018
Essex bowlers Jamie Porter and Sam Cook claimed four wickets each to condemn newly-crowned champions Surrey to a day to forget at the Kia Oval.
Only England batsman Ollie Pope made it past 20 as Surrey were skittled out for 67 in just 27 overs.
Murali Vijay and Tom Westley took full advantage as Essex reached stumps 130 ahead on 197 for two with Westley unbeaten with 93.
James Hildreth made 137 to help second-placed Somerset bat themselves into a strong position against Nottinghamshire.
— County Championship (@CountyChamp) September 24, 2018
Hildreth's contribution, as well as fifties from opener Marcus Trescothick and Steve Davies, steered the visitors to 353 for seven by the close at Nottingham with Harry Gurney taking five for 66.
Jennings was bowled for 48, but captain Liam Livingstone was still there on 46 at stumps with the visitors finishing the day on 123 for four at Southampton.
Hampshire had earlier been dismissed for 187 with Sam Northeast's 42 the most significant contribution.
In Division Two, Will Rhodes dominated an unbeaten opening partnership of 148 as second-placed Warwickshire enjoyed the better of their title showdown with leaders Kent.
Rhodes' 102 and 37 from Dominic Sibley guided their side to within 19 runs of the visitors' first innings total of 167 after Keith Barker, Chris Wright and Olly Stone had taken three wickets apiece.
Wickets tumbled at Northampton as Sussex found themselves trailing by 49 runs, five overs into their second innings at the end of day one.
Having taken four for 32 as Northamptonshire dismissed Sussex for just 118, bowler Ben Sanderson scored 36 in a 10th-wicket partnership of 60 with Ben Cotton to help his side to 171 all out, and the visitors had reached four without loss by the close.
Derbyshire opener Luis Reece struck with bat and ball to peg back Gloucestershire at Derby.
Reece's 59 provided the backbone for the home side's modest total of 184, but he then took four Gloucestershire wickets, all of them leg before wicket, to leave the visitors with 100 for five overnight.
Matt Salisbury returned figures of six for 37 as Durham took control of their clash with Middlesex in Paul Collingwood's final game for the county.
The visitors made just 121 after winning the toss and electing to bat with England bowler Mark Wood helping himself to three for 23, and Gareth Harte's 76 not out established a 106-run lead with Durham closing on 227 for five.
Glamorgan's Kiran Carlson hit 83 and Craig Meschede 55 to frustrate Leicestershire in Cardiff.
The home side will head into day two on 331 with two first-innings wickets remaining.