246 



docrome, and Pyrophyllite of Hermann, Rammelsberg, and 

 Thompson, coming to the conclusion that the last most 

 closely resembles the mineral in question ; it being the 

 only one of them, which, besides other similar characters, 

 as hardness, color, &c. possesses the singular property ex- 

 hibited by Dr. Jackson, under the influence of heat. Ram- 

 melsberg considers the mineral from Beresof and that from 

 Spa the same, from their ingredients being the same although 

 differing in quantity, and from their pyrognostic character. 

 In accordance with Dr. Jackson's remark, that the water 

 from Vermiculite restores the blue color of litmus paper, 

 Mr. Teschemacher suggested that the appearances pro- 

 duced by heat must be due to the escape of Ammonia. 

 Hence, Mr. Dana's opinion seems probably correct, that 

 these minerals are in a state of decomposition, and in this 

 condition have absorbed this alkali, so that any name 

 given to it should properly have reference to this char- 

 acter. 



Dr. C. T. Jackson said he was willing to admit the fact 

 of the close resemblance of the two minerals to each other, 

 but he must still regard them as distinct from the differ- 

 ences of their chemical formulae. 



Mr. Teschemacher alluded to a specimen of bark from 

 a South American tree recently exhibited by Dr. Hayes 

 before another Society, which is used for purposes of wash- 

 ing. It is from the Chelaia Saponaria. He gave an account 

 of the various plants possessing this property as a substitute 

 for soap. He mentioned among others the Californian 

 bulb, Phalangium pomaridianum, which has this peculiarity ; 

 and expressed the hope that any individual who might have 

 a specimen of it would place it in the hands of Dr. Hayes, 

 who was engaged at the present time in a chemical exam- 

 ination of Chelaia. 



Prof. Wyman exhibited specimens of fossil teeth of fishes from 

 the Tertiary deposit of Richmond. They belonged to the genus 



