Notes:
The head on the obverse of this coin looks nearly identical in size and style to that on the 1855 Wass, Molitor & Co. Ten Dollars.

Images courtesy of Early American History Auctions, Inc.

Varieties:
Small Head (illustrated above) 
Large Head

Significant examples:
PCGS EF-45.  Ex - Ira & Larry Goldberg Coins & Collectibles "The Fairchild Family Trust Collection" Sale, May 28-30, 2001, Lot 1135, where it was described as follows: "1855 Wass, Molitor & Co. (San Francisco) $20 Gold. Small head, Kagin-7, High rarity-5. PCGS graded EF-45. This one has excellent definition in the head of Liberty, while the reverse is a touch weak as always seen on the eagle's wings and neck. Nice rims and fields, which show only moderate handling marks. Remember, these were just "money" back when there wasn't much money around, and all coins in the Gold Rush areas circulated hard. The soft gold surfaces were prone to handling marks, and all examples have them to some degree. Luster survives in the protected areas, and this is one of the best to survive. The recent PCGS Population Report notes only 3 graded this high, with just 2 graded higher of the type! Only 11 have been graded in all, so don't expect a boatload to be available at the next auction."

Recent appearances:
"Extremely Fine, harshly cleaned (illustrated above).  Ex - Early American History Auctions, Inc.'s Mail Bid Sale, June 9, 2001, Lot 1478, where it was described as follows: "1855 Wass, Molitor & Company $20 Gold, Small Head, Extremely Fine, harshly cleaned.  A nicely detailed example of this very rare coin, but both sides have been scrubbed, the obverse rather harshly, the reverse less so. Both sides show normal circulation marks, but nothing heavy or distracting. Breen mentions that the Small Head used on this coin may be the same device punch from the 1855 $10. Fortunately, we have both types here so that we can make a side-by-side comparison and here's what we've learned: 1) the heads are nearly identical in shape and size, suggesting that the identical device punch was used on both coins. 2) the placement of the hair beads is different on both pieces, indicating that they were punched in by hand in both cases. 3) the top border of the coronet on the $20 piece is made up of beads; on the $10 it is a curved line. This may confirm that the beads were added by hand. 4) Some of the fine details may have been finished by hand, as there are slight differences between both dies. 5) The eagle on the reverse appears to have been made from the same device punch, also finished by hand on both dies. Garrett's EF brought $16,000 roughly 20 years ago, so with inflation and a strong market, this one should be worth..."

Sources and/or recommended reading:
"Walter Breen's Complete Encyclopedia Of U.S. And Colonial Coins" by Walter Breen

"Private Gold Coins and Patterns of the United States" by Donald H. Kagin