Identifying Ivory

[Simon King <sdking@sdking.demon.co.uk>]

Hi,

I've recently obtained a piece of fossil ivory which I believe dates
from the Pleistocene period approx. 120,000 BC
it was found in Oxford England 
from the Ipswichian stage.

I believe there were only two species that it could have come from,
Palaeoloxodon antiquus (Straight tusked elephant) or Mammuthus
Primigenius (Woolly Mammoth)

I'm interested in knowing if its possible to distinguish between the
different types of elephant / mammoth Ivory

I found some help at the following Web site : 

http://ash.lab.r1.fws.gov/ivory/text/elephant.html

from where I understand it's possible to distinguish between Elephant
and Mammoth Ivory by looking at the Schreger lines :

Elephant > 115 degrees
Mammoth  < 90 degrees

The Schreger lines in The piece I have are around 100 degrees 

The dimension of the tusks is as follows : 

The piece is slightly curved over it's entire length, with the large end
being circular with a diameter of 115mm, narrowing down to an oval of
90mm x 70mm. The overall length around the curve is 670mm 

My questions :

1.  Can anybody confirm that Schreger lines in Mammuthus Primigenius
(Woolly Mammoth) are < 90 degrees

2.   Can anybody tell me what measurement the Schreger lines in
Palaeoloxodon antiquus (Straight tusked elephant) are. 

3.   were there any other species around at the same time approx.
120,000 BC , Pleistocene period.

4.   Are there any other ways of telling the difference between species.

Thanks in advance.
-- 
Simon King