Colchester: University of Essex Library, Harsnett, K.d.23 i
(lists alphabetically works with book size, and occasionally date, the latest mentioned being 1595)
The dimensions given are those of a single flyleaf. The whole fragment is one unbound sheet, tall in account-book style, which has been folded over so that the stub is double thickness. This explains why, while the rectos are oriented with foot to the fore-edge, the versos have their foot to the gutter, and the fold of the stub interrupts a line of text. Each page of the sheet has a single column, with a crease -- no signs of stitch-holes -- separating the two columns. See the Babel MS for dimensions of the full leaf.