210 



NEW YORK STATE MUSEUM 



Finally, there is also evidence that already the early Cambric 

 rocks of this State may carry remains of algae. The Lower Cam- 

 bric shales contain in a number of localities in the slate belt of 

 eastern Xew York east of Albany, numerous specimens of a stately 

 form [see text fig. 14] that was first discovered by T. N. Dale 

 and has been described by Walcott 1 as O 1 d h a m i a (Murchi- 

 sonites) occidens. 



The original Oldhamia is now currently con- 

 sidered as of purely mechanical origin [see 

 Solms-Laubach, p. 50 and H. Potonie, Lehr- 

 buch der Pflanzenpalaeontologie, 1899. p. 32]. 

 O. occidens, which is by Walcott pjpvision- 

 ally referred to the calcareous algae and by Dale 

 to the nullipores, is only found as casts on the 

 surface of a smooth silicious slate and therefore, 

 notwithstanding its highly suggestive form, is 

 still a very doubtful vegetable fossil. The habi- 

 tus of the form as figured by Walcott is not that 

 of a nullipore, but rather that of one of the 

 many Florideae with whorls of branchlets 



The inference from the before stated facts is 

 that the earlier Paleozoic rocks of New York 

 contain, or are indeed partly composed of, 

 masses of calcareous algae, and that possibly these are even 

 traceable back into early Cambric time. All of these forms re- 

 quire, however, microscopic study of their structure by a com- 

 petent phytopaleontologist to establish their vegetable origin be- 

 yond doubt, and to determine their taxonomic relations by the dis- 

 covery of the propagative organs. 



No calcareous algae have as yet been made known from our 

 Devonic rocks, although their presence there can not be doubted. 

 The Devonic of this State has thus far furnished to us of indubi- 

 table algal remains, only the large Thamnocladus clarkei 

 White from the Chemung, that according to its author has the 

 greatest similarity in the external characters with the Fucaceae, 

 and the giant stem of Nematophytum eras sum from the 

 Hamilton group of Orange co., N. Y w that is in the New York 

 State Museum and is also referred to the Fucaceae. 2 



1 Walcott. C. D. Discovery of the Genus Oldhamia in America. U. S. 

 Nat. Mus. Proc. 1894. v. 17, no. 1002, p. 313-15. See also Dale, T. N. 

 Geology of the Hudson Valley between the Hoosic and the Kinderhook. 

 U. S. Geol. Sur. Bui. 242. 1904. p. 13. 



2 Pcnhallow, D. P. U. S. Nat. Mus. Proc. 1893. 16: 117. See also 

 Prosser, C. S. Am. Geol. 1902. 29: 372. 



