1 (1880) Description of the coal flora of the carboniferous formation in Pennsylvania and throughout the United States : Vol I. 1. cellular cryptogamous plants, fungi, thalassophytes. 2. vascular cryptogamous plants, calamariae, filicaceae (ferns.) ; Vol II. 1. lycopodiaceae. 2. sigillariae. 3. gymnosperms / Leo Lesquereux