There is only one cowl neckline style that looks like an unstructured, floppy turtleneck. Are you asking about different necklines? please be more clear.
Round Neckline, Square Neckline, U Shape, V Shape Neckline and Sabrina Neckline
Bateau neckline
Neckline refers to the height of the collar or neck area of a shirt or article of clothing below the chin. A high neckline might include a turtleneck while a low neckline could be a V-neck.
Rotating chimney cowl, rotating chimney cowl, spinning cowl, revolving cowl,
Richard Cowl's birth name is Richard Samuel Cowl.
on the cowl ... where else
décolleté
Fichu
A woman or girl's neckline should be no lower than two finger breadths below the collarbone. http://www.uptowngaleria.com/jewelry.html
Richard Cowl went by Dick.
A wiper cowl is something I'm trying to figure out.