Article: Plant-bearing coprolites from North American Pennsylvanian coal balls
Well-preserved coprolites are described from North American Middle Pennsylvanian age coal balls. They are composed exclusively of plant material and are divided into three types on the basis of content and gross morphology. Type A are homogeneous in composition and average 4.5 x 2.5 x 1.9 mm in size. Type B coprolites are of heterogeneous composition, measure 6.5 x 3.5 x 3.1 mm, and are the most commonly occurring type. Type C coprolites, the least common type, are amorphous in composition and have an average size of 4.5 x 2.5 x 1.8 mm. Herbivores which may have produced the coprolites are discussed and it is concluded that they were probably deposited by fossil Arthropoda.