I was researching come of my marks and found this info-  Thank you to thepotteries.org for their pics and info.

         

c. 1891+                   c.1891- 96 
                                  Royal Patent Ironstone
                   Note: name without "Ltd" also "Late R Alcock"
        Alcock had occupied the Central Pottery before Wilkinson.


       

c.1896 - c. 1910

mark is the factory name without the company name (i.e. Wilkinson)



    

c.1896 - c. 1910

mark is the factory name without the company name (i.e. Wilkinson)




c.1896 onwards
Earlier versions of this mark did not have "Ltd"




c.1907

mark is without the Wilkinson name

   

c.1910+






c.1930+



c 1929+

This pattern was introduced  from 1929 the plate this mark was one had an impressed date mark of May 1932 

   

c.1930+

The famous Art Deco "Bizarre" ware by Clarice Cliff

   

c 1930+


       

c. 1947+





date unknown