Obverse Design Legend curving above says "VICE AD : RL . OF THE BLEW : & COM : ER . IN CHIEF . OF ALL HIS . MAI : SHIPS IN THE WS . IES.". In exergue below a corded line it says "THE HON . EDWARD" and "VERNON . ESQ" in two lines. There is no line enclosing the legend. 3/4 length Vernon in the center is facing forward. His right hand is on his hip, and in his left hand he in holding a baton in front of himself. To the left of Vernon is a large tree with ground lines beneath it. To the right of Vernon it says "A . VIEW .", "OF . FORT" and "CHAGRE" in three lines. Below the legend is the fort with a steeple. Below the fort a ship is sailing right.
Reverse Design Legend curving along edge starts in the middle of the top and says "PORTO BELLO . TAKEN BY ADMIRAL VERNON . WITH SIX MEN OF WAR ONLY . NOV . 22 . ANNO DOM . 1739 .". There is no line enclosing the legend. The center is the attack on Portobello. The six ships are lined up two in the top/left row and four in the bottom/right row, those below in a curve along the bottom edge. All ships are sailing to the right. There are four small vessels in the harbor.
Distinctions There are about thirteen similar varieties with a tree. Seven of those are smaller 36 mm medals with a 1/2 length Vernon instead of a 3/4 length Vernon. Another one is a larger 54 mm by 40 mm oval. With the remaining five it comes down to the legends. Two have reversed "N"'s and the obverse legend starts with "HATH". One very similar variety has "HONLE" in exergue on the obverse instead of just "HON .". The other very similar variety has the obverse legend ending in "WEST INDIES" instead of "WS . IES".
Detail of Exergue On Obverse of VN-3.10 Detail of Legend On Obverse of VN-3.10
Detail of VN-3.10
Note the "HON" abbreviation in the exergue.
Detail of VVN-3.10
Note the abbreviation of "WEST INDIES" as "WS . IES".
Metal White metal and brass, thin and thick planchet. Weight Unknown. Size and Shape Round, 39 mm in diameter.
Rarity Common. Designer or Issuer Not known. Other Catalog Numbers Betts #279, McCormick-Goodhart #187.

Obverse legend without abbreviations and in modern English: VICE ADMIRAL OF THE BLUE AND COMMANDER IN CHIEF OF HIS MAJESTY'S SHIPS IN THE WEST INDIES.

Fort San Lorenzo at the mouth of the Chagres River is referred to as Fort Chagre on these medals.

Map of Chagres River and Fort San Lorenzo first published 1761
Map of Chagres River and Fort San Lorenzo first published 1761
From Old Panama and Castilla Del Oro by Dr. C.L.G. Anderson