Hunt.] 302 [February 18, 



Levis formation near Quebec. In Finland also these ancient 

 glauconites are found, while from Vermont he had examined 

 a glauconite of later tertiary age. Dr. Hunt had also re- 

 ceived from the late Dr. Torrey a kind of fossil resin from 

 the marl-pits of New Jersey, which had not yet been studied. 

 He referred farther to the well-known frequent occurrence 

 of a resin-like substance in the more recent coals and lignites 

 of the west, and said Dr. Newberry had observed a similar 

 matter in the paleozoic coal of Perry Co., Ohio. These 

 bodies are perhaps^ none of them identical with amber, but 

 so nearly related to it as to be of interest in this connection. 

 Dr. Hunt had also described a hard infusible resin in the 

 plant-bearing Devonian sandstones of Gaspe, on the Gulf of 

 St. Lawrence, found cementing together grains of coarse 

 sand, and constituting about one-half the weight of the rock. 

 It resembles amber, but is perhaps more nearly related to the 

 substances named scleretinite and middletonite. 



The Deposition of Clays. By Dr. T. Sterry Hunt. 



It is known to chemists that many bodies insoluble in water, when 

 in a finely divided state, remain for a long time in suspension in that 

 liquid, and readily pass with it through the pores of paper filters; 

 but that the addition to the water of a small portion of acid or saline 

 matter prevents this passage, and, moreover, causes the suspended 

 matters to subside rapidly, leaving the liquid clear. This tendency, 

 which shows itself in many uncrystalline substances, such as, for 

 example, hydrated titanic and stannic acids, and a certain modifica- 

 tion of hydrated ferric oxyd, is also very noticeable in clays. It is a 

 well known fact that clayey waters will remain turbid for days, but 

 may be readily rendered clear by the addition of a little salt or alum, 

 which soon causes the clay to settle. The turbidity of such a water 

 is, in fact, a mark of the purity or freedom from soluble salts. Prof. 

 E. W. Hilgard has lately applied this property to the mechanical 

 analysis of soils, separating the clay from the sand by suspension in 

 pure water, and afterwards precipitating it by the addition of com- 

 mon salt. He employed for this purpose one and a half parts of salt 

 to one hundred of water, but found that the half of this quantity, or 



