A Worcester cylindrical mug painted in blue with the Rock Strata Island pattern, circa 1770-80, crescent mark, 15cm high The Caughley factory made an identical version of this pattern, which when combined with its painted 'C' mark is very difficult to distinguish from the Worcester version. Lowestoft also used this design as the basis of an underglaze blue printed pattern; this, too, is quite similar to that of Worcester, but as it is printed rather than painted, is easier to distinguish. The design is directly copied from a very popular Chinese pattern.