310 Notices of Memoirs — Geological Survey of Indiana. 



believing that the latter explanation is truly the correct one. Other 

 fossils belonging to this group (such as Myriamtes) are equally, 

 beyond doubt, produced by the operations of marine animals : but it 

 remains quite uncertain whether they have been formed by Anne- 

 lidas, Crustaceans, or Mollusks. Lastly, there are remains which 

 appear to be really casts of the surface-trails of Annelides or other 

 marine creatures, and which, therefore, are elevated above the surface 

 of the bed on which they occur. Such remains may readily be con- 

 founded with those belonging to the genus Planolites, from which 

 they are only distinguishable by the fact that they are strictly con- 

 fined to a single surface of -deposition. To fossils of this nature the 

 author proposes to restrict the generic title of Nemertites. 



Finally, the author describes some singular tracks apparently 

 produced by Crustaceans belonging to the genus Ceratiocaris, and 

 for which he proposes the generic name of Caridolites. 



The following list comprises the species of fossils described in 

 this communication : — 



A. BURKOWS. 



I. Genus Aeenicolites, Salter. 



1. Arenicolites sparsiis, Salter, 



2. didymus, Salter. 



3. robustiis, Nicholson. 



II. Genus Scolithus, Haldemand. 



4. Scolithus canadensis, Billings. 

 ^ . 5. linearis, Hall. 



^^J^ 6. verticalis. Hall. 



III. Genus Histioderma, Kinahan. 

 </ 7. Histioderma hibernicuni, Kinahan. 



IV. Genus Plaijolites, Nicholson. 



8. Planolites vulgaris, Nicholson. 



9. granosus, Nicholson. 



10. articulatus, Nicholson. 



B. Trails. 

 V. Genus Ckossopodia, M'Coy. 



11. Crossopodia scotica, M.'Coj. 



12. lata, M'Coy. 



VI. Genus Nemertites, M'Leay. 



13. Nemertites Ollivantii, Murchison. 



14. {Palceochorda) major, M'Coy, 



15. {Palceochorda) minor, M'Coy. 



VII. Genus Myrianites, M'Leay. 



16. Myrianites te7%uis, M'Coy. 



17. Murchisoni, Emmons. 



C. Appendix. 

 VIII. Genus Caridolites, Nicholson. 



18. Caridolites Wilsoni, Nicholson. 



II. EePORTS of the GrEOLOGICAL SuEVEY OF INDIANA, FOR THE 



Years 1870-71-72. By E. T. Cox, State Geologist. Assisted 

 by Prof. John Collett and Dr. Gr. M. Levette, etc. (Indiana- 

 polis, 1871, 1872. London : Trvibner & Co.) 



THESE Eeports are contained in two volumes of 303 and 488 

 pages respectively, with accompanying maps, plans, sections, 

 and other illustrations of the districts described, as vrell as tables 



