1904, 1c Blue Green (4).
Left plate no. 2061 and imprint block of six, tropicalized original gum,
h.r., deep rich color, beautiful centering, Very Fine and choice (Image)
1904, 1c Blue Green, 5c Blue,
8c Gray Black (4, 6, 7). Mint N.H., rich colors, Very Fine and choice
(Image)
1904, 8c Violet Black (7).
Left plate no. 1500 and imprint block of six, h.r., few sensibly reinforced
perf separations, choice centeringEXTREMELY FINE. A RARE PLATE BLOCK OF THE 8-CENT 1904 ISSUE.
Plate blocks are known from four plates, but only from left and bottom positions. As an indication of rarity (other than catalogue value), none was offerd in the Plass sale. (Image)
1904, 10c Rose, Dropped "ON"
of "Zone" (10 var). Top center in bottom margin block of six with part
imprint, Positions 86-88/96-98, center stamps (incl. variety) Mint
N.H., others lightly hinged, brilliant color, beautiful centering,
Extremely Fine, a beautiful and rare block, the overprint variety was
corrected early in the printing process, only ten copies are recorded,
Scott Retail as hinged singles (Image)
1904, 2c Rose, Inverted Ovpt.
(10a). Mint N.H. right margin block of six with imprint, right
center stamp spaced "A L" of "Canal", rich color, Very Fine and choice,
scarce position multiple, an estimated 240 inverts were issued, this
multiple is especially desirable with the spaced "A L" variety, with 1969
A.P.S. certificate, Scott Retail as hinged singles
(Image)
1905, 2c Rose, Inverted "M" in
"Panama", Left "Panama" 16mm Long (11 var). Block of four, top left
stamp with inverted "M" in right "Panama", top right stamp left "Panama"
16mm long, tropicalized original gum, deep rich color, Very Fine and
choice, attractive multiple, Scott Retail as singles
(Image)
1905, 2c Rose, "Panama" Ovpt.
Inverted, Bar at Bottom (11b). Small part tropicalized original gum,
fresh and bright colors, choice centering, Extremely Fine, it is likely
only 200 were printed, only 35 are recorded
(Image)
1904, 5c Blue, "Pamana"
Reading Up (12). Bottom left stamp in Mint N.H. block of four (gum
slightly tropicalized), bright colors, beautiful centering, Extremely Fine
Gem, this variety occurred only on Positions 54 and 59, Scott Retail as
hinged singles (Image) 
1904, 5c Blue, "Canal Zone"
Double (12c). H.r., bright colors, clear strike of second overprint,
Very Fine and choice, this is undoubtedly from Stage V, only 200 were
printed (100 from Stage I and 100 from Stage V), ex Conger, with 1975
A.P.S. certificate (Image) 
1904, 5c Blue, "Panama" Double
(12d). Single error in horizontal strip of three, center stamp the
variety, slightly tropicalized original gum, rich colors, Very Fine and
choice, a rare variety, it is believed that 120 were printed, of these only
20 are recorded (nine unused and eleven used) -- as the red bar at top
indicates, this variety was created when the pane was fed too deeply into
the press when the second half of the pane received the overprint, causing
one vertical row to receive the two overprints
(Image) 
1904, 10c Yellow, "Pamana"
Reading Down (13 var). In pair with normal, right stamp the variety,
"Pamana" and "Panama" 1-1/2mm below bar as usual for this variety,
tropicalized original gum, brilliant color, Very Fine and choice, the
variety is known only from Positions 95 and 100, only 200 were printed (Image)