form lines are dashed. they are supposed to be used in areas where there is an obvious contour change that is not indicated by the full contour lines. i.e There is an obvious feature, but it is not as large as a full contour. I think Cliff Cave uses form lines to map the sink holes. Other examples where the elevation change might be less than a full contour: a levee, a spur that extends out into a flatter area, etc.
Yes, these were dashed. Thanks for the clarification!