Trans. N. V. Ac. Sci. 56 Dec. 12. 



composed of lapilli of soft cottony pumice, others are finer, grey, red, 

 white, etc., and contain the trunks ot coniferous trees, and in some in- 

 stances are pierced with holes which represent the stems of upright 

 plants, thickets of which were buried by the descending showers or 

 rapidly accumulating sediment of volcanic ash. Here the source of the 

 materials is to be sought in the line of great volcanic vents which 

 crown the summit of the Cascade Mountains, and from which, at inter- 

 vals, were emitted either floods of lava, poured down on to the plain 

 along the eastern border of the range, or showers of ashes which, 

 borne inland by the prevailing westerly winds, fell on forest, savannah 

 and lake, temporarily destroying animal and vegetable life, and form- 

 ing, when falling or washed into water basins, strata which alternate 

 with fossil-beds, the accumulations of quieter times. In other places 

 these tufaceous deposits were washed from all the highlands into the 

 valleys, forming local masses of considerable thickness without the 

 intercalated beds mentioned above. 



The accompanying section, copied from my report on the Geology of 

 Northern California and Oregon (Pacific R. R. Report, Vol VI, 

 Geology, p. 47), will illustrate the deposition of these tufaceous rocks 

 in the lake basins where they are interstratified with the fossiliferous 

 beds. 



Dec. 12, 1881. 



Section of Geology. 



The President, Dr. J. S. Newberry, in the Chair. 



Forty one persons present. 



Mr. N. L. Britton presented 

 *' Additional Notes on the Geology of Staten Island."* 



Two wells have recently been sunk to a considerable depth on Staten 

 Island, in the vicinity of Stapleton. One of these is on the property of 

 Mr. J. J. Cisco, near the summit of the Serpentine hills ; the section 

 as given by the Superintendent of the Pierce Well-boring Co., who 

 sank it, is as follows : 



Glacial drift 5° feet. 



Soapstone 15° feet. 



The well is six inches in diameter, and sufficient water was obtained 

 to make it a success. 



The other well is at the pump-house of Bischoff's Brewery, some 

 500 feet east of the most eastern serpentine outcrop at the foot of the 



* These notes are supplementary to the paper on this subject read by Mr. Britton on 

 April 4, 1881. (Ann. N. Y. Ac. Sci., II, i6i.) 



