Hi. The Kilner maker's mark is usually proud of the base, and covers most of the area. It is impressed onto the glass whilst the whole piece is hot, and does not tend to 'fracture off'. Yours looks very like a typical recessed pontil mark - from one of countless makers of these dumps. I have seen it suggested that these sulphides such as the boy on the elephant are late Victorian (whereas Kilner items are generally much earlier) - but I have not seen any strong evidence to support the case.