Flat Ridge Peaks

     This is an interesting side note to the main argument. In Jefferson Texas I met Jimmy Chilcutt. He examined a number of my test casts with a loupe I had brought with me. He claimed that the "ridge peaks are flat" on my test casts, while real dermal ridges, and more importantly, the CA-19 cast had rounded ridge peaks. Chilcutt drew this image on a blackboard:

     The reason that Chilcutt noticed flat ridge peaks is that the initial test casts that I sent him were made by strongly compacting the test substrates with hard plastic glued to wood chunks. Not surprisingly, the surface textures of the resulting ridges were flat, too. But other ridges created in more lightly compacted substrates, or on the sides of the casts, most certainly have round ridge peaks. This is easily verified by simply sectioning a test cast made in more lightly compacted substrate.

     As you can see, this proves not all ridge peaks are flat, as in Chilcutt's drawing. Note too, how large the ridge is, trough to trough.

    It took me a while to realize that total slurry mass is a factor in the size and distribution of the resulting desiccation ridges. It also took me a while to realize that compaction of the substrate is not a necessary condition to produce desiccation ridges. Thus the test "coupons" I sent to Chilcutt were not really representative of what more naturally produced desiccation ridges really look like.