Geology, 37l 



the terminal deposits of the Paleozoic of Ohio, the Upper Barren 

 of the older reports, known since 1891 as the Dunkard series, is 

 placed at the bottom of the Permian sj^stem, in conformity with 

 general usage. There is no general break between the Pennsyl- 

 vanian and Permian. The series has a distribution in Penn- 

 sylvania, West Virginia, and Ohio of about 8,000 square miles ; in 

 the last-named state it is now known to cover about 1,213 square 

 miles to the north and west of the Ohio River from Wheeling to 

 Pomeroy. The thickness in Ohio is about 600 feet, in Pennsyl- 

 vania from 900 to 1,000 feet, but originally the Dunkard must 

 have been considerably thicker. It consists in the main of sandy 

 shales, interspersed w^ith more or less persistent sandstones (about 

 9, having variable thicknesses that at times attain to about 35 

 feet), with impure limestones (5, usually thin but locally up to 

 16 feet thick), and with thin coals (6, only one thick enough to 

 mine, but that one 5 to 7 feet thick in places). In this way the 

 series is divided into 22 named zones. 



In Ohio, the sandstones of the Dunkard are sometimes conglom- 

 eratic and sun-cracked, more often the quartz is sharp .in grain, 

 cross -bedded, rippled, and nearly always micaceous ; in Pennsyl- 

 vania, they are more or less f eldspathic. The shales are red in the 

 upper part and in places the whole series is of the same color; 

 locally occur selenite crystals or traces of gypsum. The lime- 

 stones are more or less muddy and probably all of fresh-water 

 origin, since the only unmistakable marine fossil is Lingula per- 

 miana, n. sp., a small form restricted to a black shale associated 

 with one of the coal beds. Even though all the invertebrates are 

 described as new species, and most of them referred to marine 

 genera, they are thought to be probably forms living in fresh 

 water or on the land. All are small, and most of them exceed- 

 ingly so. They include 4 bivalves, 3 gastropods, Spirorhis, and 

 ostracods. In addition, there are fish scales and ganoid teeth, at 

 least one large dorsal shark spine, the dorsal spine of a reptile 

 (Edaphosaurus), and coprolites. At the base of the Dunkard 

 occurs the Cassville shale, which in West Virginia has yielded 

 a Permian flora of 107 species, and a number of cockroach wings ; 

 in Ohio, however, only 21 plant species have been noted. 



The reviewer gets the impression from the book that the climate 

 of Dunkard time was still warm, though tending to become more 

 and more arid, that the gradually subsiding coastal swamp area 

 of the Dunkard lay near sea-level, and that but rarely did the sea 

 back water far into the region of this earliest of Permian deposi- 

 tions. The report is especially valuable for any one who wishes to 

 dig out the environmental conditions of the time through the 

 detailed presentation of the many local exposures. c. s. 



3. The Stratigraphy and Paleontology of Toronto and Vicin- 

 ity, Part I, The Pelecypoda; by Beatrice Helen Stewart. 

 Twenty-ninth Ann. Rept., Ontario Dept. Mines, pp. 1-59, 5 pis., 

 1920. — It is interesting to note the revival of interest in the local 

 paleontology of the strata about Toronto. It is proposed first to 



