so usually these bands of ultra mylonite
 
are a centimeter are so thick here in
one case in this case we see one that
has been subsequently pinched out and as
it continued to mylonize the rocks
continued to shear is spun into this
beautiful spiral shape called a delta
delta porphyra blast for porphorclast
I'm sorry and in other locations here we
see a layer of ultra mylonite this
black rock that's over a foot thick
that's an amazing amount of this
material and could accommodate really a
remarkable amount of you know perhaps
tens of meters of strain over this small
interval and the other remarkable thing
about this is that you would never guess
if you if I picked it up and handed it
to you you might say oh that's Flint
another fine grain siliceous Rock this
has probably started out as a granite
and you would never guess the
parent rock once it's been
recrystallized to this fine a grain size
all the rocks begin to look the same and
so it's really only by geochemical
analysis that we could tell what the
original rock was
