Here we have a very pretty green oval platter, it is much more of a green than what turned out in the picture.   On close inspection and turning sideways into the light you can see some knife markds but when not inspecting as close as I did you would not notice these. No chips.  I have been told this is the RAINBOW shape - IPattern names and pattern numbers used here come from advertisements in pottery industry trade magazines published during the time the W. S. George Pottery Company was in business, and from backstamps of actual pieces. Some more recently published antique price guides and collector books give names to patterns that have become common usage.  This is stamped WS George Made in U.S.A. 180B.

The names of shapes were almost always on the bottoms of pieces, and are often mistaken for the pattern name.  A shape name refers to the shape of the clay mold.  The same pattern often had a different name when used on a different shape. Shape names include Lido, Bolero, Radisson, Elmhurst, Fluerette, etc. 

Pattern numbers, if present, are most often seen on the bottoms of platters and creamers.  this doesn't have one.  They were usually 4-8 digits in length, with mixed numbers and letters.   Most WSG pieces have a 4 digit (3 numbers and a letter) code on the bottom which is often mistaken for the pattern number.180B