368 [Dec. ■. 



Silicic Oxide (SiO 2 ) 55.880 



Titanic Oxide (TiO 2 ) 1.270 



Sulphuric Oxide (SO :) ) 0.022 



Alumina (Al 2 O s ) 21.849 



Ferrous Oxide (FeO) 9.033 



Manganous Oxide (MnO) 0.586 



Cobalious Oxide (CoO) trace 



Lime (CaO) 0.155 



Magnesia (MgO) 1.495 



Soda (Na'O) 0.460 



Potash (K 2 0) 3.640 



•Carbon(C) 1.794 



Water (H 2 0) 3.385 



Iron Bisulphide (FcS 2 ) 0.031 



Total 99.800 



Mr. McCreath added a note which is not at hand, but to the effect that 

 he believed this 1.794 p. c. of carbon (so common an ingredient in Hudson 

 river rocks) was not in the form of graphite. 



Carbon might be looked for lower as well as higher than the horizon as- 

 signed to the chlorite series, but, if the former, it would be more likely to 

 appear as graphite. 



The following extracts from a letter of President Rendall 

 to Professor Frazer, in answer to further inquiries as to the 

 genuineness of the fossil, are of importance in view of the 

 length of time which may possibly elapse before another 

 specimen is brought to light. 



In 1875, I visited the quarries in company with Dr. S. B. Howell of 

 Philadelphia I am not certain whether he obtained a speci- 

 men at that time. I think he did of the rock but not of the fossil. I went 

 from quarry to quarry inquiring of the old workmen and of the owners, 

 whether they had at any time seen any marks on the slate. The answer 

 for the most part was no ; but two of the more experienced workmen said 

 they had noticed some marks, but they had a vague notion of them, and 

 could not give an adequate description. They thought they had seen them 

 recently, and searched some piles of slate without success. 



I left an order with them to preserve for me any specimens which might 

 turn up. They promised in a friendly way to keep whatever might be 

 found. There was no promise of money. They did not expect reward, and 

 had no reason to procure specimens to deceive, unless for the pleasure of 

 deceiving. They were to notify the resident Pres. minister who promised 

 to take possession for me. In a little while they sent word to him that they 

 had found some marks on a slab, lie omitted to go for it, or to notify me, 



* Average of three determinations. 



