Geology and Mineralogy. 75 



The age of the plants is " Lower Carboniferous," and the same 

 horizon is present in Spitzbergen. Eleven species are figured or 

 described, but of these only five are specifically identified. These 

 are Calymmutotheca bifida, Sphenophyllum tenerrimum elonga- 

 tion (also in the Pottsville), AsterocalamU.es scrobiculatus, Lepi- 

 dodendron spetsbergense (and three other species), Lepidophyllum. 

 cfr. lanceolatum, and Stigmaria Jicoides. c. s. 



12. On a Trenton Echinoderm Fauna at Kirhfield, Ontario; 

 by Frank Springer. Mem. No. 15-P, Dept. Mines, Canada, 

 Geol. Surv. Branch. Pp. 50 and 5 heliotype plates, 1911. — While 

 excavating the Trent canal in the lower Trenton limestone much 

 excellent echinoderm material was obtained from 25 to 80 feet 

 above the Black River, all of which is here listed or described. 

 Of crinoids there are 26 species (2 new), edrioasterids 4, cystids 

 3 and starfishes 5. The " most remarkable fossil echinoderm " 

 Hybocystis is described in detail and illustrated in 12 fine figures 

 on Plate II. An entire colony was found in which more than 

 100 specimens were crowded into a space of a few square feet. 

 Four-fifths of these are H. eldonensis Parks. The genus is 

 remarkable because it has but 3 erect blunt arms, the other 2 

 being recumbent as in some cystids and fastened to the calyx 

 plates. Much labor has also been devoted to Cupidocrinus, 

 which is not far removed from the radicle that gave rise to the 

 order Flexibilia present at this locality in 2 species of Protaxo- 

 crinus. Interesting remarks are made on Oleioerinus regius, 

 which has the calycine pores and pore-rhombs of the cystids, and 

 the species is referred to as a " case of premature secession from 

 the cystids." Astroporites ottawaensis Lambe, originally regarded 

 as a probable bryozoan, is here said to represent "the lower part, 

 or floor, of an unusually highly organized root of a crinoid, con- 

 solidated by growth into a calcareous plate for attachment to flat 

 surfaces." The illustrations are remarkably fine drawings by K. 

 M. Chapman. c. s. 



13. Geology of the Thousand Islands Region / by H. P. 

 Cushing, H. L. Fairchild, R. Ruedesiann and C. H. Smyth, Jr. 

 New York State Museum, Bull. 145, pp. 194, many illustrations 

 and 6 maps, 1910. — A most excellent and detailed geologic, strati- 

 graphic and petrographic report of an interesting area. The 

 basement rocks are of the Grenville series, and are more or less 

 overlapped from the east by the thin Potsdam sandstone and 

 Theresa dolomite of Upper Cambrian age. On this follows a short 

 erosion interval, and then a submergence from the south, the 

 Beekmantown limestone, another erosion period followed by a 

 little of the Stones River limestone (Pamelia), a third lost inter- 

 val, and then a long marine invasion, the Mohawkian (Lowville, 

 Watertown, and Trenton) limestone. The Pleistocene geology 

 is by Professor Fairchild. c. s. 



14. Geology of the Poughheepsie Quadrangle ; by C. E. Gor- 

 don. New York State Museum, Bull. 148, pp. 117, geological 

 map and many illustrations, 1911. — The geology of the Pough- 



