Four wickets in the first 10 overs have put Yorkshire in control of their LV= County Championship Division Two match against Gloucestershire at Scarborough.
The hosts had their opponents nine for four in an astonishing start which saw Steven Patterson take three scalps.
Benny Howell and Dan Housego both fell to the 28-year-old for ducks, before Hamish Marshall (four) became his third victim. Moin Ashraf dismissed Rob Nicol for four and although Ian Cockbain (28) and Will Gidman (30) are unbeaten at lunch, after electing to bat Gloucestershire are in trouble at 70 for four.
At Chelmsford Essex are 78 for four, with Derbyshire vindicated in their decision to bowl after winning the toss.
The wickets were shared around by the visiting attack with Tony Palladino, Tim Groenewald, Mark Turner and David Wainwright all successful.
Palladino made the early against his former county after he had Jaik Mickleburgh caught by Tom Poynton for five, before Tom Westley (14), Owais Shah (26) and Mark Pettini (14) all made starts before they were dismissed.
Northamptonshire, who still harbour hopes of breaking into the top two are 58 for two at the break against Glamorgan at Cardiff with opener Niall O'Brien still at the crease unbeaten on 23.
After choosing to bat the visitors lost Stephen Peters for 23 after he was bowled James Harris before Graham Wagg had David Sales caught by wicketkeeper Mark Wallace for 11. Alex Wakeley has joined O'Brien and is nine not out.
Kent are currently 80 without loss after 23 overs leaving Leicestershire to regret choosing to field after winning the toss at Grace Road. The game began at mid-day due to rain and Sam Northeast is unbeaten on 35, while captain Rob Key is 37 not out.
There was no play before lunch in the match between Lancashire and Durham due to a wet outfield.