This prosaic cover is one of a dozen or so openings of a long drainage canal running roughly in the center of the Long Meadow in Brooklyn's Prospect Park. Towards the end of the line near the Picnic House are the classic BP (Brooklyn Parks) covers(see below), but then the further north you go it seems there were replacements made - such as this one. The size of this cover is the same as the BP covers and it also has the somewhat unusual lip overhang them as well.
The single strand basket weave design is about as generic as they come. This one has tapered stitches that seem to have been a bit more common in the early 20th century than now. The rings of possibly drilled vents are not too common.
Both a drain for surface water and a service entry for cleaning the underlying channel.
This item is towards the north end of the Long Meadow along the line of covers from the Picnic House valley to the Endsdale Arch. In its particulars, this cover appears to be unique.