Here is the earliest item from the Molineaux Webb pressed glass catalogue. These plates were numbered in order of production. By the time the catalogue was produced circa 1870, plates 1,2,3 had gone but plate 4 was still in production.
This one is going to be particularly controversial because it can be seen on the front cover of Raymond Notley's slim Shire book on glass, and is described within as an American lacy plate. This was probably due to Ruth Webb Lee including this design in her books on American glass, but here we have it sitting in the Molineaux Webb catalogue.
Even better, I have acquired two of these though eBay, and one of them is an extremely early primitive pressing. I believe it to be one of the earliest pressed pieces in the UK which can be attributed to a glass works. This plate 4 design was probably moulded circa 1835 and this particular pressing can't be too much after that.
If you look at the photos there are 4 signs of its early date. Firstly, the lacy pattern, on the back of the plate, fades off towards the bottom, a sign of a poor quality pressing. Secondly, it is possible to stand the plate up on one of the frills. The frill at the bottom is not chipped - it's another pressing fault. Thirdly, the thickness of the glass, seen in the edge on shot, indicates it is early.
Last and most interesting, there are six press marks around the bottom of the bowl where the glass has been "squeezed" in the pressing machine. I have never seen this type of mark on any other piece of pressed glass. It's a bit difficult to see in the photo - I have arrowed it.