Lodge skillet heat rings at various points had no notch, a single notch (at 12), and 3 notches. There is currently a propensity on the part of many to attribute any skillet with a raised size number on the top of the handle and a raised molder's mark at 6 o'clock on the bottom to the Blacklock Foundry, in which Joseph Lodge was involved before establishing the foundry that bore his name. Little is known about Blacklock skillet production, as it appears they, like Lodge for most of its production, didn't mark their skillets with a name, although they did other pieces. The RB shows a skillet with an outside heat ring and a raised letter molder's mark which it conjectures may be Blacklock. The short period in which the Blacklock foundry existed tends to suggest that their skillets would have been of the outside heat ring design. But there are no skillets known for certain to be Lodge that do not have inset heat rings. There is also an article published which attempts to connect various skillets with similar characteristics into a "Blacklock/Lodge" timeline.