No. II. 



Description and Chemical Analysis of the Retinasphalt, disco- 

 vered at Cape Sable, Magothy River, Ann Arundel County, 

 Maryla?id. By G. Troost, M. D.^Read iQth Dec. 1833. 



In the American Journal of Sciences and Arts edited by 

 B. Silliman, (Vol. III. p. 8) I published a description of a va- 

 riety of amber, and of a fossil substance supposed to be a 

 nest of an insect, discovered at Cape Sable, Maryland This 

 description was the result of only one analysis. It appears 

 now, from subsequent trials, that there occur, at that place, 

 two minerals, which are very similar in their appearance, 

 viz. the true amber, and a resino-bituminous substance 

 known by the name of Retinasphalt. It happened, acciden- 

 tally, that I selected, for the first analysis, some fragments 

 of the true amber ; and in consequence, taking for granted 

 that it was all the same substance, as the hardness, smell 

 when burnt, ^-c. appeared to be the same, I described it in 

 the above mentioned Journal as amber. Having returned 

 to my former residence, where I have every means to 

 vary my researches, I have submitted this substance again to 

 examination, and have discovered my error, and ascertained 

 that it consists of two, if not of three, others, of some- 

 what different nature, viz. amber, Retinasphalt, and a sub- 

 stance which corresponds with what Jameson calls iossil 

 copal. 



I have now the honour to lay before the Philosophical 

 Society the result of my investigations. 



