104 PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 
In an upper bed of the igneous rock, close upon the spot where a patent 
slip has been cut, amygdules of the size of the fist occur among others of agate : 
these amygdules are totally filled, not with concentric layers of chalcedony, but 
with celadonite. The concentric structure is evidenced by brownish bands ; 
the structure is granular, and the material of the layers is not so pure as that 
analysed above. 
At Hare-Craig, on the opposite side of the Tay, this mineral rarely occurs in 
thin veins, of a very brilliant colour. 
4, From the same line of railway, but near its western extremity, where it 
joins the Tay Bridge. 
The mineral here is in veins, which frequently consist solely of a granular 
mixture of calcite with celadonite ; the pure mineral was obtained with diffi- 
culty. It was granular, but never in mammillated coatings. Its specific gravity 
was 2° 598. 
It yielded on 1°3 grammes— 
Silica, , ee 
From Alumina, . ORT 
683 = 52° 538 
Alumina, . : . or 824 
Ferric Oxide, . ‘ . -O ele 
Ferrous Oxide, . ; ., 9°4 
Manganous Oxide, . 307 
Lime, ; 4 eimade ene4S) 
Maenesia, : 98 8807 
Potash;” -. : ; sin 166. GAG 
Soda, : ’ ; ; ° 635 
Water, . ; : , lOeezhls 
100 + 927 
Loses 3° 879 per cent. of the water at 212°. 
