Probably 127 film, which was commonly exposed either as 12 4.5cmx4.5cm images or 8 4.5cmx7cm images. There was never a Kodak standard for shooting 16 exp / roll, as there was for the larger 620 and 120 sizes, but there were a very few cameras that did (e.g. Foth Derby). The negs could be 620 or 120 shot 16exp / roll.
If 16exp 120/620, they would have been shot vertically across the width of the roll so all would have exactly the same long dimension (2.4"/61mm) and would vary slightly in their width as a result of the cutting. If 127, they would have been shot horizontally down the length of the roll and would all have exactly the same short dimension (46mm) with slightly varying long dimensions.