walcott.] PALEONTOLOGY UPPER MISSISSIPPI. 223 



(Figs. 5, 12), together with figures of Lingula antiqua and L. prima, and 

 a number of others placed under Obolus and Orbicula. 



Mr. Edward Daniels stated in 1859 that upon a small island in Black 

 River he had found perfect impressions of crustaceans consisting of 

 double rows of parallel tracks, precisely like those in Montreal. 1 (Pro- 

 tichnites of Logan. — C. D. W.) 



In the report of the superintendent of the geological survey of Wis- 

 consin, Prof. Hall describes, from the Potsdam sandstone: 2 



Lingula polita, p. 24. Theca primordialis, p. 48. 



Lingula aurora, p. 24. Serpulites murchisonia, p. 48. 



In the geological volume he illustrates : 3 



Graptolithus(Dendrograptus)hal- Theca primordialis, p. 21. 



lianus, p. 21. Serpulites murchisonii, p. 21. 



Liugula polita, p. 21. Dikelocephalus rainnesotensis, p. 



pinnaf'orinis, p. 21. 22. 



antiqua, p. 21. D. pepinensis, p. 22. 



aurora, p. 21. 



In a letter to Principal J. W. Dawson, Prof. Hall describes a new 

 crustacean from the Potsdam sandstone under the generic name of 

 Aglaspis, stating it to be the same form mentioned in a communication 

 to the Albany Institute. 4 



In 18G2 Prof. G. H. Hitchcock published a list of the fossils of the 

 Potsdam group in North America, including in it all the species known 

 to him described from the Potsdam sandstone and also from the strata 

 now referred to the Cambrian of other parts of North America. The 

 list includes one hundred and thirty-four species. 5 



In 18G2 Prof. B. F. Shumard describes from the Potsdam sandstone 

 of Wisconsin and Missouri the following species: 6 



Dikelocephalus latifrons, p. 101. 

 Arionellns bipunctatus, p. 101. 

 Conocephalites minor, p. 105. 



He also noticed under the name of Conocephalites iowensis, the Dikel- 

 ocephalus (?) ioivensis of Owen (p. 102), and Grepicephalus (?) wisconsensis, 

 under the name of Conocephalites wisconsensis (p. 103). The Loncho- 

 cephalus chippewaensis Owen and L. hamulus are both referred to the 

 genus Conocephalites (p. 101). A species of Agnostus was referred to 

 Agnostus orion (?) of Billings (p. 105). 



1 Notes on geology of Wisconsin and adjacent States. Eostoa Soc. Nat. Hist. Proa, vol. 6, 1859, p. 

 310. 



2 Keport of the superintendent of the geological survey (of Wisconsin), exhibiting the progress of 

 the work. January 1, 1861. Madison, 1861, pp. 52. 



■Physical geography and general geology. Geol. Surv. Wisconsin, Report, vol. 1, 1862, pp. 1-72. 



4 On a new crustacean from the Potsdam sandstone. Canadian Naturalist, vol. 7, 1862, p. 445. 



•Fossils of the Potsdam group in North America. Portland Soc. Nat. Hist. Proa, vol. 1, 1862, pp. 

 87 00. 



6 Notice of some new and imperfectly known fossils from the Primordial zone (Potsdam sandstone 

 and Calciferous Sand-group of Wisconsin and Missouri. St. Louis Acad- Sci. Trans., vol. 2, 1862, pp. 

 101-105. 



