386 



ON MEECUEY IN ALLUVIAL DEPOSITS. 



By Dr. J. J. Watsojt, E.G.S. 



Dr. Phipsoij-, of Paris, has drawn attention, in the April number 

 of the Geologist, to the observations which have been made of the pre- 

 sence of mercury in the soil and substrata of the town of Montpellier, 

 and, in your June number, another correspondent notices the finding of 

 the same metal under circumstances so decidedly adventitious, how- 

 ever, as to possess, I think, rather archaeological than geological inte- 

 rest. The occurrence of this precious metal in rocks and mineral 

 deposits of such ages as we should hesitate to assign for its matrix, most 

 probably arises from its fluid nature admitting of its easy transport to 

 distances far remote from those formations in which it exists in situ ; 

 and, as furnishing something like the history of its presence in such 

 apparently abnormal situations, the following account of its discovery at 

 Ajaccio, in the Island of Corsica, may, perhaps, be considered worthy 

 of insertion : — 



In the year 1811, a M. Matthieu, an Engineer Officer of the Prench 

 Army, was entrusted by Napoleon with the mineral survey of the 

 Island, but, being re-called to his military duties in 1814, was cut off 

 before Leipzig, leaving in the possession of his widow the notes he had 

 made of his survey. These notes do not appear ever to have been 

 officially communicated, but among them was a memorandum to the 

 efl'ect that a deposit of mercury existed at Ajaccio. In 1847, a sewer 

 was in course of construction near the barracks of the gendarmerie, 

 at the Place Mourou ; and, in trenching below the vegetable soil, a 

 large quantity of metallic mercury was found disseminated through the 

 earth in minute globules — it is calculated that about 270 cart-lo^ds of 

 this mercuriferous soil were removed. Owing, however, to the persons 

 engaged in making the drain being ignorant of its value, but a very 

 small quantity of the metal was preserved, and, beyond the ordinary 

 curiosity which such an occurrence would excite, the circumstance does 

 not seem to have met with any attention until 1850, when a fresh 

 quantity was discovered in digging the foundation of some houses in 

 the Place Mourou, at a distance of about 500 yards from the locality 

 where it was first found. This time attention was roused, and the I 

 existence of an important deposit capable of being profitably exploited 



