200 Thirty-fifth Report on the State Museum. 



consists of elongated cells (fig. 7), with somewhat thick walls, and 

 more dense toward the circumference. The walls of these cells pre- 

 sent acurious reticulated appearance, apparently caused by the cracking 

 of the ligneous lining in consequence of contraction in the process of 

 carbonization. Imbedded in this outer cylinder are about twelve vas- 

 cular bundles (figs. 2, 3, d), each with a dumb-bell-shaped bundle of 

 scalariform vessels inclosed in a sheath of thick-walled fibres. Each 

 bundle is opposite to one of the rays of the central axis. The speci- 

 men shows about two inches of the length of the stem, and is some, 

 what bent, apparently by pressure at one end." 



" This stem is evidently that of a small tree-fern of a type, so far as 

 known to me, not heretofore described,* and constituting a very com- 

 plex and symmetrical form of the group Palaeozoic Ferns, allied to the 

 genus Zygopteris of Schimper. The central axis alone has a curious 

 resemblance to the peculiar stem described by Unger ("Devonian 

 Flora of Thuringia") under the name of Clacloxylon mirdbile ; and 

 it is just possible that this latter stem may be the axis of some allied 

 plant. The large aerial roots of some modern tree-ferns of the genus 

 Angiopteris have, however, an analogous radiating structure." 



The specimen is from the collection of Berlin H. Wright, Esq., of 

 Penn Yan, New York, and was found in the Portage group (Upper 

 Erian) of Milo, New York, where it was associated with large petioles 

 of ferns and trunks of Lepidodendra, probably L. chemungense and L. 

 prirncevum." 



" In previous communications to the society I have described three 

 species of tree-ferns from the Upper and Lower Devonian of New York 

 and Ohio ; and this species is from an intermediate horizon. All four 

 occur in marine beds, and were, no doubt, drift- trunks from the fern- 

 clad islands of the Devonian sea. The occurrence of these stems in 

 marine beds has recently been illustrated by the observation of Prof. 

 A. Agassiz, that considerable quantities of vegetable matter can be 

 dredged from great depths in the sea on the leeward side of the Carib- 

 bean islands. The occurrence of these trunks further connects itself 

 with the great abundance of large petioles (Rhachiopteris) in the same 

 beds, while the rarity of well-preserved fronds is explained by the 

 coarseness of the beds and also by the probably long maceration of the 

 plant-remains in the sea-water." 



Nowhere in the county does the rock change in character sufficiently 

 to warrant the sub-divisions which Prof. Hall gives to this group in 

 Livingston and Alleghany counties. The entire thickness of the group 

 in Yates county cannot be less than 1,000 feet. 



* Prof. Williamson, to whom I have sent a tracing of the structure, agrees with me that 

 it is new. 



