]898.] NATURAL SCIENCES OF PHILADELPHIA. 99 



nary way with balsam indicated beneath the microscope that nearly 

 every particle had crystallized into a mineral. Groups of three or 

 six crystals were recognized with a low power objective. In polar- 

 ized light some of the crystals showed extinction parallel to the 

 longer axis. 



A pile of rubbish, which had been dug out of the bone-bed-fissure 

 from which Professors Mercer and Cope had selected all that was 

 worth having, contained some bone fragments in which the cellular 

 structure of bone could be observed and also the gradual transition 

 into the mealy condition or complete metamorphosis of bone phos- 

 phate into a mineral. I think a better proof could hardly be given 

 of the gradual metamorphic change that has taken place in that 

 locality. It seems to me that this fissure, which is V-shaped, had 

 no outlet for the water which soaked the mixture of bones, ferrugi- 

 nous clay, twigs, fragments of sandstone, etc. and that the oppor- 

 tunity for mutual chemical dissociation was favorable to that effect. 

 That carbon dioxide along with the water effected the change from 

 the organic to the mineral in this case as in many others, scarcely 

 requires demonstration. The phosphoric acid seemed to have been 

 transposed and- reunited with ferric oxide and with alumina to form 

 vivianite and similar minerals, as indications of the presence of these 

 species were noticed in the pile of debris near the bone deposit. In 

 order to give some further proof of the almost complete change of 

 the bone substance from the chemical standpoint, I endeavored to 

 find the quantity of the carbonic acid gas volumetrically. I ob- 

 tained by two measurements the average of 24.045 cubic centimeters 

 at 0°C. temperature and 760 millimeters pressure of carbonic acid 

 gas from 100 milligrammes of the mineral. This reduced to mass 

 equals 47.23 per cent. It is evident that this rather high result must 

 have a cause. Either there is another gas, or there is another oxide 

 beside the lime. On determining the bases a large quantity of 

 magnesia was found. The following is the result of the analysis: 



CaO 30.39 per cent. 



MgO 20.83 per cent. 



C0 2 47.23 per cent. 



Insoluble 1.79 per cent. 



100.24 



The insoluble part consisted mostly of sand, a trace of lime phos- 

 phate and oxide of iron. If these small quantities of phosphoric 



