A New Pachytesta from the Berryville Locality of Southeastern Illinois

Abstract

Recently several differenit kinds of petrified seeds belonging to the pteridosperms have been discovered in coal-ball material from the Berryville locality, Lawrence County, Illinois. The largest and most frequently found is Rotodontiospermumn illinoense Arnold and Steidtmann (1937). N:eely (1951) reported Conostoma quadratum Graham-n (1934) and a new genus Coronostoma, which like Conostoina is a small seed having its affinities with Lagenostomales. Genera of Trigonocatpates found at the locality, other than Rotodontiospermumn, are Stephanospermum and Pachytesta. Stephanosperrnum is represented by a single spcciine1i2 ald Pachytesta by four.3 Three of the pachytestas are medium-sized (2.5-3.0 cm. Ilong) one of which is well preserved; the fourth is small (about 1.0 cm. long) whose size and general aspect is similar to Pachytesta pusilla, (Brongniart) Hoskins and Cross (1946b). Two petrified seeds showing structure and characters of the genus Pachytesta were reported in American coal-balI material by Krick (1932). The material was associated with No. 5 coal of tihe O'Gare Mine, Harrisburg, Illinois. Subsequently Reed (1939) described two seeds from the Allegheny series at Polks -Patch near, Boonville, Indiana and called them Pachytesta gigantea no. 1 and no. 2. These were later reinvestigated by Hoskins and Cross (1946b) and assigned to a new species, P. noei. Pachytesta vera was described by Hoskins and Cross (1946a) from the Des Moines series near Oskaloosa, Iowa. These five seeds represent the extent of described members of the genus Pachytesta in American petrifactions. rhis paper deals with th4 description of a new species of Pachytesta from Berryvilie coal-ball material; effort is also made to relate it to other species of Pachytesta and to cther genera of the Trigonocarpales as well.