98 THE CANADIAN NATURALIST. [Dec. 



the green hornblende (pargasite) from Pargas in Finland. This 

 mineral there occurs in a crystalline limestone with fluor, apatite, 

 chondrotite, pyroxene, pyrallolite, mica and graphite; associations 

 very similar to those of the serpentine of Steinhag. The grains 

 of pargasite, although completely crystalline within, and having a 

 perfect cleavage, are rounded on the exterior, curved inward and 

 outward, and also approximatively cylindrical in form ; so that 

 they may be best compared with certain vegetable tubercles. If 

 the crystalline carbonate of lime which accompanies the pargasite 

 is removed by an acid, there remains a mass of pargasite grains, 

 generally cohering, and presenting a striking resemblance to the 

 skeleton obtained by submitting the Eozoon serpentine-limestone 

 to a similar treatment. The tubercles of pargasite are then seen 

 to be joined together by short cylindrical projections, which are 

 however readily broken by pressure, causing the mass to separate 

 into detached grains. The highly crystalline and ferruginous 

 carbonate of lime which is mingled with the pargasite, shews no 

 organic structure either when etched or examined in thin sections ; 

 although the pargasite presents forms similar to those observed in 

 the serpentine of Steinhag. The surfaces of the curved cylindrical 

 and tuberculated grains of pargasite are in part naked, and in part 

 protected by a thin white covering. In some parts fine cylindrical 

 growths are observed, and in others cylindrical perforations passing 

 through the grains of pargasite. By a careful microscopical 

 examination of the surface of these grains (PL I., fig. 8), 

 numerous small tubuli, sometimes two millimeters in length, are 

 clearly seen, and by their exactly cylindrical form may be readily 

 distinguished from other pulverulent, fibrous and acicular crystal- 

 line mineral matters. These cylinders consist of a white substance, 

 which contrasts with the dark green pargasite, and have the 

 diameter of the tubuli of Eozoon, or from -rtjftu to rMu millimeters. 

 A single large cylinder was also observed lying obliquely across 

 between two of the pargasite tubercles. (PI. I., fig. 8 a.) In 

 the decalcified specimens, a white mineral, probably scapolite, was 

 observed side by side with the green pargasite ; sometimes forming 

 groups of tubercles like the latter ; while in other cases a single 

 tubercle was found to be made in part of the green and partly of 

 the white mineral. From these observations there can scarcely 

 remain a doubt that these curiously rounded grains of pargasite 

 imbedded in the crystalline limestone of Pargas represent the 

 casts of sarcode-chambers, as in the Eozoon ; and that they 



