234 
GEOLOGIC FORMATIONS. 
four toises thick; and this geological fact proves on the one 
hand the identity oi the alpenkalksteiii with the zechstein of 
Thuringia, and on the other the affinity of formation existing 
between the alpine limestone and that of the Jura.* The 
strata of marl effervesce with acids, though silex and alumina 
predominate in them : they are strongly impregnated with 
carbon, and sometimes blacken the hands, like a real vitriolic 
sclnstus. The supposed gold mine of Cuchivano, which was 
the object of our examination, is nothing but an excavation 
cut into one of those black strata of marl, which contain 
pyrites in abundance. The excavation is on the right bank 
of the river Juagua, and must be approached with caution, 
because the torrent there is more than eight feet deep. The 
sulphurous pyrites aro found, some massive, and others crys- 
tallized and disseminated in the rock ; their colour, of a very 
clear golden yellow, does not indicate that they contain 
copper. They are mixed with fibrous sulphuret of iron.t 
and nodules of swmestone, or fetid carbonate of lime. The 
marly stratum crosses the torrent ; and, as the water washes 
The Jura anil the Alpine limestone are kindred formations, and they 
are sometimes difficult to be distinguished, where they lie immediately 
one upon another, as in the Apennines. The alpine limestone and the 
zechstein, iamons among the geologists oFFreybcrg, are identical formations 
fills identity, which I noticed in the year 1793 (Uber die Grubcnwetter), 
is a geological tact the more interesting, as it seems to unite the 
northern European formations to those of the central chain. It is known 
that the zechstein is situated between the muriatiferous gypsum and the 
conglomerate (ancient Sandstone); or where there is no muriatiferous 
gypsum, between the slaty sandstone with roestones (liunte sandstein 
Wean ), and the conglomerate or ancient sandstone, ft contains strata 
of schistous and coppery marl (Intuminoce mergel and kupferschiefer' 
winch form all important object in the working of mines at Mansteld in 
kaxony, near Riegelsdorf in llcsse, and at Hasel and Pransnitz.in Silesia. 
,.lmmi' !i era Part 0f Buvan * (Oberbaiern), I saw the alpine limestone, 
thin^e S 1 i CSBS T e Strat n ° f schistous cla I and marl, which, though 
thmnei winter, and especially more frequent, characterize the limestone 
of Jura. Respecting the slates of Hlattenberg, in the canton of Gians 
which some mineralogists .because of their numerous impressions offish, 
have long mistaken lor the cupreous slates of Mansteld, they belon* 
according to M. von Bueh, to a real transition formation. All these 
geological data tend to prove that strata of marl, more or less mixed 
with carbon, are to be found in the limestone of Jura, in the alpine lime- 
stone, and m the transition schists. The mixture of carbon, sulphuretted 
iron and copper, appears to me to augment with the relative antiquity oi 
the formations. f Haarkics. 
