527 



form, becomes divided (c, d) ; in one division (d) the compacted fibres 

 change into aciculi, distinctly separated. 



Similar asbestiform veins, more or less parallel to the last, occur on 

 each side of it : indeed, the specimen, a slab a few inches in length, is 

 in one part intersected by a number of the same kind of veins, dividing 

 it into thick sub-parallel plates, which by further subdivision would 

 become converted into layers of " chamber casts." Other important 

 changes, to which serpentine is subject, remain to be noticed. 



Dr. Carpenter's section, examined by transmitted light before it was 

 decalcified, showed very distinctly a number of striking examples of the 

 " canal system but still no proper idea could be formed as to their 

 origin and nature. Decalcified, and examined as opaque objects, how- 

 ever, an important light was thrown upon them. 



Like other specimens, noticed in our former Paper, the one now 

 under examination occasionally shows the passages that had been 

 occupied with the calcareous matter of the " intermediate skeleton" clog- 

 ged with flocculite ; and this substance occurring as " white amorphous 

 masses." Fig. 7 (PI. XLIIL), represents a passage, unusually wide, con- 

 taining one of these " masses" of considerable size, which is broken up (A, 

 B), and divided into thickish plates — straight, curved, or wavy— lying 

 close and parallel to one another, or opening out and again conjoining re- 

 peatedly, or variously diverging.* The plates themselves also break up 

 into a great variety of slender configurations, that are filamentous, 

 foliaceous, arborescent, palmate, or rod-like ; and elliptical, circular, 

 or crescentic in their transverse section : in short, there seems to be 

 no limit to the variety of " shapes" assumed by the plates of flocculite. 

 This substance varies also in texture, being spongy, granular, or com- 

 pact ; in the last state resembling dense snow, from which condition it 

 occasionally passes into one resembling imperfectly translucent ice ; ©r 

 it assumes the character of serpentine, having precisely the green colour, 

 varying in shade and translucency, of this mineral. 



The various forms presented by the flocculite in this section, especially 

 the arborescent, are certainly beautiful ; and when a number of the 

 different kinds are clustered together in the same field of view, a more 

 pleasing sight cannot be revealed by the microscope. 



Our former investigations made us acquainted with examples, lead- 

 ing us to adopt the conclusion (previously arrived at by Dr. Carpenter) 

 that the " amorphous masses" and "definite shapes" are no more than 

 " modifications of one type;" but we had no idea of meeting with a 

 specimen so completely demonstrative of this view. We now go further. 

 In Dr. Carpenter's section, the edge of the serpentine, contiguous to 

 the example of the u canal system" represented in Pig. 7, B x, is seen 



* It is a source, of much regret that we find ourselves unable to give any more 

 than a rude sketch of one (simple compared with many) of the numerous examples 

 which the section displays; but we have taken every pains to represent its leading points 

 as truthfully as possible. 



E, I. A. PKOC. VOL. X. 4 A 



