3872, 7. S. Hunt— Quartz and Silcification in Calfornia. 
Dr. Hunt, in commenting upon this occurrence, remarked 
that it is in accordance with what we already know of the re- 
cency of some of the quartz of this region, and cited the micro- 
scopic studies of John Arthur Phillips, who has shown that a 
great part of the siliceous deposit from certain thermal waters 
of Lake County, California, and from the Steamboat Springs of 
asbestus. The various specimens from this locality illustrate 
perfectly the theory of silicification of vegetable structures, set 
forth by the speaker in 1864,* based on his own microscoplé 
studies conjoined with those of Géppert and of Dawson. 
The silica by which the tissues are thus successively filled 
and replaced is, according to the speaker, that which is set free 
in a soluble form in the decay of the silicates in the gravel. The 
lignite in the undecomposed and unoxidized portions of this 
which lie below drainage-level is, as yet, unsilicified. Dr. Hunt 
acknowledged his obligations to Mr. D. T. Hughes, a member 
of the Institute of Mining Engineers, in charge of the mine 1D 
question, and a skilled and careful observer, who had called his 
attention to the facts just set forth. 
Professor W. C. Kerr stated that his recent and as yet UD- 
published observations on the fossil woods found in ancient 
gravels in North Carolina were in accordance with those ¢¢ 
scribed by Dr. Hunt. 
* See Can. Naturalist, New Series, vol. i, p. 46; also Hunt’s Chem. and Geol. 
Suga tes, ralist, 8, i, p. 
