DISCOVERY OF THE GENUS OLDHAMIA IX AiMElflCA. 



By Charles D. Walcott, 



Honorary Curator of Paleontology. 



In 1865 Prof. James Hall referred a fossil found associated with 

 Buthoyraptus iu the Trenton Limestone at Plattville, Wis., to the genus 

 Oldhamia, under the specific name of fruticosa* He described this 

 form as " stems of corneus or carbonaceous texture, frecjuently branched, 

 the branches again dividing and sometimes, if not always, iu whorls, 

 in one of which six divisions were counted.'* Prof. Hall's reference to 

 Oldhamia was tentative and, from the study of Dr. J. R. Kinnehan'st 

 beautiful illustrations of the genus Oldhamia, I am led to think it 

 exceedingly doubtful if the species fruticosa should be referred to it. 



Prof. Charles Lapworth mentions the occurrence of an Oldhamia in 

 the purple slates of Farnham, Province of Quebec, like 0. radiata, 

 but does not describe or illustrate it.t It is placed in the horizon 

 of the Upper Cambrian. Dr. R. W. Ells, of the Geological Survey of 

 Canada, writes me that the Farnham slates belong to the Sillery for- 

 mation. A i^oorly preserved specimen, received from the Sur\ey, 

 proves the presence of Oldhamia, but does not afford data for a specific 

 determination. 



During the field season of 181)3, Mr. T. Nelson Dale, while surveying 

 the areal geology of the Troy sheet of the U. S. Geological Survey, 

 collected, in a belt of reddish shale that extends north and south, 

 west of the Rensselaer plateau, a lot of annelid trails and plant-like 

 impressions, which were sent to me with other material for determina- 

 tion. The only form that I can identify is a species of Oldhamia that 

 is closely related to Oldhamia antiqua of the Cambrian rocks of Ireland. 



* Canadian Organic Remains, Decade ii, 1865, p. 49. 

 t Trans. Royal Irish Acad., xxiii, 1859, p. 547. 

 t Trans. Roy. Soc. Can., iv, 1877, Table A, p. 183. 

 Proceedings of the U. S. National Museum. Vol. XVII — No. 1002. 



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