LV=County Championship Division Two, Sophia Gardens, Cardiff (day two):
Yorkshire 500 (122 overs): Shan Masood 192, Bean 93, Hill 71; Harris 3-131, Carlson 3-147
Glamorgan: 150-6 (50 overs): Carlson 53*, Byrom 40; Revis 3-20
Glamorgan (2 pts) trail Yorkshire (7 pts) by 350 runs with four first-innings wickets remaining
Shan Masood's 192 and a three-wicket burst from Matthew Revis put Yorkshire in a dominant position at the close of day two against Glamorgan.
Yorkshire were bowled out for 500 in their first innings, as 93 from Finlay Bean and 71 from George Hill boosted their total.
The hosts collapsed to 150-6 in reply, with 53 not out from Kiran Carlson their only real defiance.
At the close of play, Glamorgan need 201 to avoid the follow-on.
A delayed 11:00 BST start saw Glamorgan's first official concussion replacement, as Dan Douthwaite came in for Ben Kellaway after the spinner hit his head on the ground fielding on day one.
However, due to Douthwaite's seam bowling not being deemed a 'like-for-like' replacement for Kellaway's spin, he was not able to bowl.
Yorkshire's Hill added 20 to his score overnight before he was trapped LBW by James Harris for 71.
He was followed by Jonathan Tattersall, who clipped a leg-side Andy Gorvin delivery to Chris Cooke behind the stumps for six, while Revis dragged an attempted reverse-sweep off Carlson onto his own stumps for 28.
Masood was batting serenely through a six-hour stay with scarcely a scare, hitting 17 fours, running hard between the wickets, and looking set for a double century until he was caught at cover off Harris.
Jordan Thompson was gone too the next ball, and Ben Coad and Ben Cliff fell cheaply, leaving Dom Bess on 28 not out and Yorkshire with a very healthy total as they claimed maximum batting points.
After a long day-and-a-half in the field for Glamorgan, Carlson and Harris finished with three expensive wickets each.
In reply to Yorkshire's total, Zain ul Hassan was the first to go for Glamorgan, as Coad rocked back his off stump for eight.
Colin Ingram was out shortly afterwards in similar style, as his off stump was sent cartwheeling by Thompson for five.
With Yorkshire on top, 20-year-old Cliff marked his first over in the County Championship with a maiden and tested the outside edge of Byrom.
Sam Northeast made 16 before missing an attempted cut shot off off-spinner Dom Bess, before Revis took over and sent Glamorgan heading towards a likely follow-on.
Bryom was his first victim, as after a well-made 40, he flashed at a wide ball outside the off stump.
Next came Billy Root, as a sharp short ball looked to deflect off Root's arm through to keeper Tattersall.
Revis' third brought about the demise of Chris Cooke LBW, with Glamorgan 100-6.
Concussion replacement Douthwaite (17 not out) and captain Carlson (53 not out) battled to make it through to the close of play, as Glamorgan finished on 150-6.