Obverse Design Legend curving above says "THE . PRIDE . OF . SPAIN . HUMBLED . BY . AD : VERNON". There is a die break near the word "BY" obscuring that area. There is a faint line enclosing the legend. A full length Vernon is on the left, facing 3/4 to the right, wearing a tricorn hat; his left hand is extended and in his right hand he is receiving the sword of Don Blass. Don Blass is on the right and facing left (towards Admiral Vernon), and is on his left knee. His right hand is handing his sword to Admiral Vernon and his left hand is holding his hat behind him. His left foot extends into the "O" of "VERNON". Behind Don Blass's shoulder on the right is a small ship sailing to the right. In the field above Don Blass's head is the legend "DON BLASS" with the "N" reversed. Admiral Vernon and Don Blass are on a platform above a corded line. Below the corded line is a lions head ornament with leaves to the right and the left. The medal has beads along the rim.
Reverse Design Legend curving along the top starts with an ornament of a small leaf resembling a butterfly and then says "HE . TOOK . PORTO . BELLO . WITH . SIX . SHIPS . ONLY". There is an inside line enclosing the legend. In exergue (under a line along the bottom of the medal) it says: "NOV . 22 . 1739". There are no ornaments below the date, but there is a die break under the "17". The center is the attack on Portobello. The six ships are lined up one in the top row, two in the middle row and three in the bottom row. All the ships are sailing to our right. There are water lines under the bottom row of ships. There is a boat below the fort on the right, and a man is in it with both arms raised. No boats are in the harbor. A short tower points at the second "L" and a a steeple at between the "W" and "I". The medal has beads along the rim.
Distinctions There are about fourteen varieties where Don Blass is kneeling in front of Admiral Vernon. In five of these Don Blass is on one knee, and in three there is a complete ship to the right of Don Blass. Of the three, one is smaller at 34 mm and has a tower and shaft pointing at the first "L" and the "I". The other two (made from the same original dies) have a short tower pointing at the second "L" and a steeple pointing at between the "W" and the "I". The differences are then quite minor between the last two. VN-166 has a higher mast on the ship on the front and a heavier waterline under it, the word "PRIDE" was recut to make it more regular and there is the die break around the word "BY" on the obverse.
Detail On Obverse of VN-4.62 Detail On Reverse of VN-4.62
Detail of VN-4.62
Note the high mast on the ship and the heavy waterline under it.
Detail of VN-4.62
Note the spire at the second letter "L", and the steeple between the "W" and "I".
Metal Brass and copper. Weight Unknown. Size and Shape Round, 39 mm in diameter.
Rarity Common. Designer or Issuer Not known. Other Catalog Numbers Betts #307, McCormick-Goodhart #166.

Sources do not appear certain about the reversal of the "N" in Don Blass, and the "N" is mostly worn away in the example above.

To respond to the comment written on the map about Fort San Fernando missing - Fort San Fernando was built in 1753 and the map was drawn in 1736.

Map of Portobello drawn in 1736
Map of Portobello drawn in 1736
From The Panama Guide by John Collins