

walcott.] PALEONTOLOGY ADIRONDACK. 231 



In 1856 Dr. Emmons published a description of Lingula prima Em- 

 mons, Lingula antiquata Emmons, and L. acuminata Conrad. The two 

 latter speeies are illustrated on PI. iv, but in the description of the 

 plate the figure of Lingula antiquata is called L. prima by error. 1 



In I860. Prof. F. H. Bradley described and illustrated Coyiocephalites 

 minutus from the Potsdam sandstone at Au Sable Chasm, near Keese- 

 ville, New York. 2 



The announcement of the discovery of another type of track in the 

 Potsdam sandstone was made by Sir W. E. Logan, in 1860. For this 

 he proposed the name Climactichnites icilsoni. 3 



In 1869 Prof. O. C. Marsh described a new species of Protichnites 

 .from the Potsdam sandstone of Essex County, Xew York, naming it 

 J *ro I ich n i tes log a n a n u 8, A 



As the result of comparative study of diiferent tracks, Dr. J. AY. 

 Dawson concluded that Protichnites of Owen was possibly made by 

 some Limuloid crustacean. 5 



From collections made at Keeseville, New York, Messrs. Hall and 

 Whitfield described the genus PaheacmaBa, the type species being 

 Palaacmwa typica and Hyolithes gibbosa. 6 



In 1877 Mr. E. J. Chapman says that the fossil tracks known as Pro- 

 tichnites and Climactichnites are of such a nature that he does not con- 

 sider them to be of animal origin : and he suggests that they are noth- 

 ing more than impressions of large fucoids. If this idea be accepted 

 he proposes to change the names to Protichnides and Climactich- 

 nides. 7 



From the limestone in Saratoga County, New York, in which Mr. J. 

 H. Steele noticed the large concentric concretions, Mr. C. D. Walcott 

 described in 1879 the following species : 8 



Platyceras minntissiinuni,p. 129. 

 Metoptoma cornutiforme, p. 129. 

 Conocephalites calciferns, p. 129. 

 Conocepbalites harttii, p. 130. 

 Ptychaspis speciosus, p. 131. 



The presence of a species closely allied to Batliyurus armatus of Bil- 

 lings was noticed; also Stromatopora sp. ?, Lingula acuminata, Metop- 



1 American Geology, containing a full statement of the principles of the acience, with fall ilustra- 

 tions of the characteristic American fossils. Albany, 1856, vol. 1, pt. 2, pp. 232, 203. 



* Description of a new trilobite from the Potsdam sandstone. Am. Jour. Sci., 2d ser., voL 30, 1860, 

 p. 241. 



3 On the track of an animal lately found in the Potsdam formation. Canadian Nat., vol. 5, 1860, pp. 

 ! 285. 



4 Description of a new species of Protichnites from the Potsdam sandstone of New York. Am. Jour, 

 i .. 2d ser.. vol. 48, 1809, pp. 46-49. 



' Impressions and footprints of aquatic animals and imitative markings on Carboniferous rocks. 

 Am. Jour. Sci., 3d ser., voL 5, 1873, p. 17. 



6 Notice of two new species of fossil shells from the Potsdam sandstone of New York. 23d Rep. 

 New York State Mns. Nat. Hist.. 1873, p. 242. 



7 On the probable nature of the supposed foesX tracks known as Protichnites and Climactichnites. 

 Canadian Jour. Sci., Lit. and Hist.. n< vol. 15, 1877, p 490. 



* Descriptions of new species of fossils tiom the Calciferous formation. 32d Rep. N. Y. State Mus. 

 NaU Hist., 1679, pp, 129-131. 



