1866.] KING AND EOWNET — '' EOZOONAL EOCIi." 205 



pyrosclerite, chlorite, &c. ; but associated with them are numerous 

 "white amorphous masses" of a granular texture — some vitreous, and 

 others opaque. The tufts are aggregations of stout, tapering, slightly 

 translucent crystals, which divide or rudely radiate, strike oif from 

 points on the surface of the ''chamber- casts," spring out of the 

 " amorphous masses," or lie imbedded in the residual calcite of the 

 passages. The crystals are not so slender as those in the Conne- 

 mara Ophite ; nor do any of them, individually or aggregately, show 

 such a decided tendency as those of the latter rock to simulate the 

 Canadian dendritic ramifications*. 



If so few " definite shapes " occur in the Connemara Ophite, they 

 are undoubtedly well represented by numerous crystalline aggrega- 

 tions, which, together with the '' amorphous masses," occupy the 

 decalcified passages, often to the almost entire exclusion of the cal- 

 careous matter proper to the ''skeleton" or septa f. The cr^'stals, 

 which are acicular, and separated, or in contact, variously diverge, 

 radiate, or intersect one another, shooting athAvart the passages in 

 all directions. The aggregations may be completely followed into 

 the true " definite shapes," already noticed, through a variety of in- 

 termediate forms t. 



The conformity between the Connemara and Grenville varieties 

 of Ophite, declares Dr. Carpenter, " is so close as to leave no doubt 

 on my mind as to the organic origin of the former." "I find, in place 

 of a continuous asbestiform layer covering the segments §, long 

 straight bundles of asbestiform filaments radiating from them. 

 What is the import of these — whether they represent a part of the 

 original structure of the animal, or are (as I am disposed to suspect) 

 a product of subsequent metamorphism — is a point which must be 

 reserved for further investigation" ||. If our interpretation of the 

 supposition contained in this passage be correct, it implies that, in 

 Dr. Carpenter's opinion, the crystalline aggregations were originally 

 " definite shapes " — internal casts of tubular passages — w^hich have 



* This Ophite presents a somewhat unusual appearance, inasmuch as the 

 *' chamber-casts " are aggregated in the form of comparatively thin plates, 

 which frequently anastomose, producing a sort of network, its meshes, which 

 are wide, being the " calcareous septa." Nor are the " chamber-casts " in general 

 so neatly segmented as in other varieties of Ophite. They are composed of two 

 kinds of minerals : one, of an impure leek-green colour, displays, on fracture, 

 a lamellar cleavage, with pearly planes ; the other is darker, often quite black. 

 The former is possibly pyrosclerite, and the latter may be impure loganite. 

 They are occasionally coated with a forest of short slender diverging crystals, 

 which might be taken to represent the " proper wall." 



t See PL XV. fig. 13. In this example the crystalline aggregations are less 

 numerous than usual, and they are remarkably free from the " white amorphous 

 masses." 



X We find these aggregations to be soluble in hot sulphuric acid, like the 

 granules and other " eozoonal" parts ; from which it may be inferred that they 

 are composed of a hydrous silicated magnesia, and consequently cannot belong 

 to a variety of pyroxene or augite. They probably represent another allomorph 

 of serpentine, and are in all probability a more crystalline form of metaxite. 



§ The asbestiform layer, however, as will have been seen, docs exist in Con- 

 nemara Ophite. 



II Intellectual Observer, vol. vii. pp. 297, 298. 



