Below is shown a section of the various strata at the Glyn Pits. The thickness of the coal measures was:

​

At 52 yards depth was the 'Soap Vein' at 2 feet six inches.

​

At 88 yards was the 'New Vein' or Elled coal, at 4 feet.

​

At 104 yards was the 'Droideg' coal, or 'Big Vein'.

​

At 117 yards was the 'Red Vein' or 'Three-Quarter coal' at three feet eight inches.

​

At 143 yards was the 'Rock Vein' or 'Black Vein' at eight feet.

​

At 149 yards was the 'Yard Vein' coal, at two feet six inches.

​

At 152 yards was the 'John Williams' coal at 12 inches.

​

At 171 yards was the 'Meadow Vein', at ten feet two inches.

​

At 178 yards was the 'Old Coal' at five feet six inches,

​

And at 190 yards was 'Rough Coal' at one foot ten inches.

​

As will be seen, there were various other strata including ironstone, which was also mined at the Glyn Pits.

​