Hello Paul,

these are pyrobitumen, bitumen and/or oil inclusions.There is a relatively recent paper on them by O'Reilly and Parnell (1999) in the GSA Bulletin:

http://bulletin.geoscienceworld.org/content/111/12/1884

Hope this helped.

Best wishes,

Max

Max is correct.  According to the literature these are the mineral Antraxolite.  See "Little Falls Formation" here:

http://www.nysm.nysed.gov/publications/record/vol_03/chapter03/

Dear Max and John,

Thank so much for sheding light on the nature of these enigmatic spheroids.  I always thought they were  composed of organic matter, perhaps a petroleum-like substance. Your answers are very definitive.

Best wishes, Paul.