APPENDIX. 189 
moft natural to account for the formation of thofe famous 
maffes of lilver found feparate at Guantajaia, about which fo 
many extravagant and ridiculous ftories have been told. 
The mats of iron, which is the fubjeft of this letter, ac- 
cording to its cubic meafure, and allowing it a little more 
fpecific gravity than iron, muft weigh about 300 quintals. 
(Sig.) Chev. MICH. RUBIN DE CELIS. 
From the Ifland of Leon, 
June 20, 1786. 
