86 PROCEEDINGS OF THE PHILADELPHIA MEETING 



souri, and the Galena limestone type of Wisconsin and the Fenorite of the 

 Mississippi Valley have had such au origin. 



Eead in full from maiinscri]:»t. 



Discussion 



Mr. John Johnston : I understand that the hlood of oysters and similar 

 animals contains copper, this copper heing to some extent analogous to the 

 ii'on in the hiemoglohin of human blood. 



Dr. Frank R. Van Hokx : I have been much interested in Professor Van 

 Ingen's paper, which has treated a new subject from a paleontologic physio- 

 logic standpoint. For some years I have been of a similar opinion, which was 

 arrived at on account of cliemico-minera logic reasons. The association of lead 

 and zinc ores with dolomitic limestones is well known, from various parts of 

 the Mississippi Valley as well as certain places in (Germany. The association 

 of lead with limestones can be explained by the isomorphism of the carbon- 

 ates of calcium, barium, strontium, and lead in the minerals aragonite. wither- 

 ite, strontianite, and cerussite. The association of zinc with limest(mes can be 

 explained by the isomorphous calcite group, which consists of calcite, dolo- 

 mite, magnesite, siderite, rhodochrosite, and, lastly, smithsonlte, which is zinc 

 carbonate. Doctor \'an Ingen's reasons for assuming that the tissues of vari- 

 ous mature animals absorb metallic salts will hold equally true for their shells 

 and other hard parts which are secreted by the soft parts, and it is the hard 

 parts which originally formed the limestone beds. It Is very clear that there 

 must have been a chemical rearrangement of compounds, since the metals are 

 found now as sulphides and sulphates. We know that most limestone has 

 been more or less dissolved and recrystallized. In this rearrangement the car- 

 bonates of the metals may likewise have been dissolved and subjected to re- 

 ducing solutions which have resulted in galena, sphalerite, barite, and celestlte. 



Further remarks were made by Messrs. T. L. Watson and W. H. 

 Emmons. 



The section adjourned at 5.1 T) o'clock p. m. 



PRESIDENTIAL ADDRESS 



At 8 o'clock p. m. the Society convened in the lecture hall of the 

 Academy of Natural Sciences and listened to the reading by Vice-Presi- 

 dent W. Lindgren of an abstract of the address of retiring President 

 George F. Becker, entitled 



TSOfiTASY AND RADIOACTIVITY 



Publislied as pages 171-204 of this volume. 



The address was followed by the complimentary smoker given in honor 

 of the Geological Society of America and the Paleontological Society by 

 the local members of the former organization. 



