Oct. 1906] PROCEEDIXGS S. 1. ASS\\ ARTS AND SCIENCES. 7C) 



the schists, are fully discussed, ending with a discussion of the final proc- 

 esses of weathering- and superficial disintegration and dissociation of 

 the rock into ferruginous quartz and limonite, which is such a promi- 

 nent feature on Staten Island. Mention is also made of the "occa- 

 sional slight concentration of chromite, magnetite, and perhaps spinel," 

 and "talcose and chloritic alteration of lime and magnesia carbonates, 

 in particles and veinlets of calcite, dolomite and hydromagnesite, with 

 concentration on Manhattan Island, at West 59th Street, as ophicalcite 

 in cavities of the serpentinoid." 



The granite on the shore at Tompkinsville and beneath the water at 

 the mouth of the Kills near St. George is accepted as evidence of "an ex- 

 tensive pegmatite intrusion underneath the serpentinoid ridge." In re- 

 gard to the associated gneiss or schist, denominated "gneissoid gran- 

 ite," the author says: "The latter structure, probably marginal, must 

 have resulted from movements while the igneous mass was still in par- 

 tially molten condition.'' 



The granitic and gneissic composition of the reefs and islets in New 

 York harbor is mentioned and the inference is deduced that "the ba- 

 sic intrusion [the present serpentinoid ro;k] in the gneiss, now forming 

 the ridge on the west bank of the Hudson, was followed, as on Man- 

 hattan Island, by intrusions of pegmatite. These found the tough ma- 

 terial of the overlying basic sill impenetrable, except perhaps on the 

 north line of the present Kill van Kull. Along this plane of weakness, 

 after elevation, the ensuing erosion of the acid rock resulted in excava- 

 tion of the mouth of the Kill and in separation of part of the serpentin- 

 oid ridge, on Staten Island, from its continuation on the mainland at 

 Jersey City and Hoboken." 



The concluding part of the paper deals with general descriptions and 

 comparisons of the serpentinoids and their associated rocks in neigh- 

 boring states and the discussion of the former volcanic activites which 

 must have prevailed in the region. — A. H. 



II. "On Cretaceous Pityoxyla." E. C. Jeffrey and M. A. Chrysler. 

 Bot. Gaz.,\o\. xlii, igo6, pp. i — 14, pis. i, ii. 



In this paper, in addition to the description of a specimen from Scit- 

 uate, Mass., the authors include the results obtained from microscopic 

 examinations of lignites obtained from the clay beds of Kreischerville. 

 Three different genera were identified in the material collected there: 

 Ara2icarioxylon, CiiPressinoxylon, and Pityoxylon. Specimens in 

 the latter genus are made the special subjects of the paper, and a 

 new species is described and figured under the name PUyoxyloa 



