Weller — Kinderhook Fanned Studies. 127 



very youngest Devonian. It yet remains to be demonstrated, 

 however, whether or not the Kinderhook holds such a rela- 

 tionship to the Carboniferous of other parts of the world. 



EXPLANATION OF ILLUSTRATIONS. 

 Plates I. -IX. 



(ALL OF THE FIGURES ARE OF NATURAL SIZE.) 



Plate I. — 1-2, Productus laevicostus White. Pedicle and lateral views 

 of an average specimen. U. of C. Coll., No. 5924. — 3-4, Productus cooper - 

 ensis Swall.? Anterior and lateral views of a specimen identified as this 

 species by A. Winchell. U. of M. Coll., No. 2000. — 5-6, Productus semi- 

 reticulatus Martin. Lateral and anterior views of an average specimen. 

 U. of M. Coll., No. 1336. — 7-8, Productus semireticulatus Martin. One of 

 the type specimens of P. curtirostris Win., which proves to be the brachial 

 valve of P. semireticulatus. U. of M. Coll., No. 1337. — 9-10, Productella 

 nummularis (Win.). A pedicle and a brachial valve, two of the type speci- 

 mens. U. of M. Coll., No. 1340. — 11-13, Schizophoria sicallovi (Hall). The 

 two larger specimens are a brachial and a pedicle valve. The smaller speci- 

 men is a pedicle valve which was used by Winchell as the type of Orthis 

 Jlava. U. of M. Coll., Nos. 1351 and 2007. — 14, Chonetes illinoisensis 

 Worthen. A somewhat distorted specimen. U. of C. Coll., No. 5925. — 15, 

 Chonetes sp. undet. An imperfect impression of the brachial valve. U. of 

 C. Coll., No. 5926. — 16, Chonetes sp. Cf. C. geniculata White. An internal 

 cast of the pedicle valve. U. of C. Coll., No. 5927. — 17, Chonopectus fischeri 

 (N. & P.). Illustration of an average pedicle valve. After Hall. — 18, 

 Orthothetes inaequalis (Hall). A cast of a pedicle valve taken from a natural 

 mould. U. of C. Coll., No. 5928. —19, Orbiculoidea capax (White). The 

 type specimen. U. of M. Coll., No. 1331. — 20, Lingula membranacea Win. 

 The type specimen. U. of M. Coll., No. 1330. 



Plate II. — 1-3, Syringothyris extenuatus (Hall). Anterior and posterior 

 views of an average specimen. U. of C. Coll., No. 5929. A very large 

 brachial valve. U. of M. Coll., No. 1365. — 4-5, Bhynchonella sp. undet. 

 Two specimens showing the variation in form. U. of C. Coll., No. 5930. — 

 6-7. Spirifer biplicatus Hall. Views of a pedicle and a brachial valve, the 

 pedicle valve preserving the mucronate extension of the hinge-line on one 

 side. U. of C. Coll., No. 5931. — 8-10, Spirifer subrotundatus Hall. Pedi- 

 cle, brachial and anterior views of an average specimen. U. of C. Coll., No. 

 5932. — 11, Reticularia cooperensis (Swall). View of a brachial valve. 

 U. of C. Coll., No. 5933. — 12-15, Athyris corpulenta (Win.). Views of two 

 of the type specimens. U. of M. Coll., No. 1359. — 16-17, Pugnax striato- 

 costata (M. & W.) var.? Pedicle and anterior views of an average speci- 

 men from the Chonopectus sandstone. U. of M. Coll., No. 1375. — 18-19, 

 Eumetria altirostris (White). Brachia and pedicle views of a nearly perfect 

 specimen. U. of C. Coll., No. 5934. 



Plate III. — 1-2, Pterinopecten Cf. P. laetus H. A large, flat, right valve, 

 and a smaller left valve. The left valve here illustrated was one of the 



