This picture shows three views of a ridged or crested blade. These blades are actually initial core reduction waste flakes. They represent one type of preparatory blade removal before the desired blades were struck from the core or nuclei. The ridge or crest can be seen in the view to the right. After the rough outer surface cortex was removed sometimes one or two sides of a core was trimmed to a vertical ridge and struck off to shape a good starting point for later blade removals.
These blades were then used to make a wide variety of tools.