525 



like asbestos," and which we hold to be typical chrysotile. Further- 

 more, the fibres, as already pointed out, likewise become gradually or 

 abruptly changed into white glistening aeiculi, retaining their juxta- 

 position, or separated from one another by well-marked interspaces — • 

 now open, but filled with calcite before decalcification. 



The serpentine granules have their surface also often changed into 

 a white flocculent substance,* which may be granular, coarsely platy, 

 fibrous, or acicular : these variations are well seen in Pig. 3 (PL XLI.) 

 taken from one of Dr. Carpenter's sections. 



The divisional peculiarities, when on the large scale, as in the cases 

 first noticed, cut the serpentine into a variety of forms, with rounded 

 or hollowed surfaces, rudely resembling both acervuline and laminar 

 " chamber casts :" in many cases the resemblance is so striking as at 

 once to suggest the idea that the forms are examples of " chamber 

 casts" in process of formation. "When calcite occupies the divisional 

 interspaces, as often happens (or rather was the case before decalcifica- 

 tion), it may be conceived that such calcareous intercalations are 

 examples of the "intermediate skeleton" in course of elaboration. 



Dr. Carpenter's section, the first one brought under notice, affords nu- 

 merous cases of the above modifications. Over a considerable portion of it 

 may be seen, as represented in Pig. 4 (PI. XLI.) long parallel divisions 

 (c), in some places completely, or imperfectly closed — in others, more or 

 less open : the latter condition is due to the removal of the calcite conse- 

 quent on decalcification. The closed divisions are partially, or entirely 

 filled up — sometimes with flocculite — generally with a crop of fibres or 

 aeiculi, separated and in contact, projecting from their sides. Occasion- 

 ally the serpentine, forming the sides of these divisions, is incipiently, 

 or completely chrysotilized ; and in numerous cases there is the same 

 passage from " asbestiform fibre" to separated aeiculi, as seen on the sur- 

 faces of " chamber casts." 



That these divisions are nothing more than cracks, is rendered 

 palpable by all their appearances, especially by their intersecting 

 uninterruptedly the layers of " chamber casts" (a), as well as the cal- 

 careous intercalations (b) forming the so-called " intermediate skeleton." 



Reverting to cases of the same kind which occurred to us while 

 engaged with our former Paper : we pointed them out as totally 

 destructive of the opinion that ascribes the " asbestiform layer" topseu- 

 dopodial tubulation ; and we adduced an example unmistaheably on our 

 side.] How has it been disposed of ? Dr. Carpenter affirms to having 

 met with " numerous examples" of the kind, but " so destitute of the 

 characters of the true asbestiform layer," that he has " no hesitation in 

 regarding" them " as either originally a product of inorganic agencies, 

 or as the result of metamorphic changes in a structure originally 

 organic" Sow can such an argument be handled ? If we lay hold of 

 the " inorganic" side, it slides over, and presents the "organic" one! 



* Called flocculite in our former Paper. 



f "Quarterly Journal of Geological Society," vol. xxii., p. 196, Plate xiv., fig. 4. 



