life is dawn on the earth 26

life is dawn on the earth 26

In conclusion of this part of the subject, and referring to the notes

appended to this chapter for further details, I would express the hope

that those who have hitherto opposed the interpretation of Eozoon as

organic, and to whose ability and honesty of purpose I willingly bear

testimony, will find themselves enabled to acknowledge at least the

reasonable probability of that interpretation of these remarkable forms

and structures.

 

 

NOTES TO CHAPTER VII.

 

(A.) Objections of Profs. King and Rowney.

 

_Trans. Royal Irish Academy, July, 1869._[AO]

 

[Footnote AO: Reprinted in the _Annals and Magazine of Natural

History_, May, 1874.]

 

The following summary, given by these authors, may be taken as

including the substance of their objections to the animal nature of

Eozoon. I shall give them in their words and follow them with short

answers to each.

 

"1st. The serpentine in ophitic rocks has been shown to present

appearances which can only be explained on the view that it undergoes

structural and chemical changes, causing it to pass into variously

subdivided states, and etching out the resulting portions into a

variety of forms--grains and plates, with lobulated or segmented

surfaces--fibres and aciculi--simple and branching configurations.

Crystals of malacolite, often associated with the serpentine,

manifest some of these changes in a remarkable degree.

 

"2nd. The 'intermediate skeleton' of Eozoon (which we hold to be

the calcareous matrix of the above lobulated grains, etc.) is

completely paralleled in various crystalline rocks--notably marble

containing grains of coccolite (Aker and Tyree), pargasite (Finland),

chondrodite (New Jersey, etc.)

 

"3rd. The 'chamber casts' in the acervuline variety of Eozoon are

more or less paralleled by the grains of the mineral silicates in the

pre-cited marbles.

 

"4th. The 'chamber casts' being composed occasionally of loganite and

malacolite, besides serpentine, is a fact which, instead of favouring

their organic origin, as supposed, must be held as a proof of their

having been produced by mineral agencies; inasmuch as these three

silicates have a close pseudomorphic relationship, and may therefore

replace one another in their naturally prescribed order.

 

"5th. Dr. Gümbel, observing rounded, cylindrical, or tuberculated

grains of coccolite and pargasite in crystalline calcareous marbles,

considered them to be 'chamber casts,' or of organic origin. We have

shown that such grains often present crystalline planes, angles, and

edges; a fact clearly proving that they were originally simple or

compound crystals that have undergone external decretion by chemical

or solvent action.

 

"6th. We have adduced evidences to show that the 'nummuline layer' in

its typical condition--that is, consisting of cylindrical aciculi,

separated by interspaces filled with calcite--has originated directly

from closely packed fibres; these from chrysotile or asbestiform

serpentine; this from incipiently fibrous serpentine; and the latter

from the same mineral in its amorphous or structureless condition.

 

"7th. The 'nummuline layer,' in its typical condition, unmistakably

occurs in cracks or fissures, both in Canadian and Connemara ophite.

 

"8th. The 'nummuline layer' is paralleled by the fibrous coat which

is occasionally present on the surface of grains of chondrodite.

 

"9th. We have shown that the relative position of two superposed

asbestiform layers (an _upper_ and an _under_ 'proper wall'), and the

admitted fact of their component aciculi often passing continuously

and without interruption from one 'chamber cast' to another, to the

exclusion of the 'intermediate skeleton,' are totally incompatible

with the idea of the 'nummuline layer' having resulted from

pseudopodial tubulation.

 

"10th. The so-called 'stolons' and 'passages of communication

exactly corresponding with those described in _Cycloclypeus_,'

have been shown to be tabular crystals and variously formed bodies,

belonging to different minerals, wedged crossways or obliquely in the

calcareous interspaces between the grains and plates of serpentine.

 

"11th. The 'canal system' is composed of serpentine, or malacolite.

Its typical kinds in the first of these minerals may be traced in

all stages of formation out of plates, prisms, and other solids,

undergoing a process of superficial decretion. Those in malacolite

are made up of crystals--single, or aggregated together--that have

had their planes, angles, and edges rounded off; or have become

further reduced by some solvent.

 

"12th. The 'canal system' in its remarkable branching varieties is

completely paralleled by crystalline configurations in the coccolite

marble of Aker, in Sweden; and in the crevices of a crystal of spinel

imbedded in a calcitic matrix from Amity, New York.

 

"13th. The _configurations_, presumed to represent the 'canal

systems,' are _totally without any regularity_ of form, of relative

size, or of arrangement; and they occur independently of and apart

from other 'eozoonal features' (Amity, Boden, etc.); facts not only

demonstrating them to be purely mineral products, but which strike at

the root of the idea that they are of organic origin.

 

"14th. In answer to the argument that as all the foregoing 'eozoonal

features' are occasionally found together in ophite, the combination

must be considered a conclusive evidence of their organic origin,

we have shown, from the composition, physical characters, and

circumstances of occurrence and association of their component

serpentine, that they represent the structural and chemical changes

which are eminently and peculiarly characteristic of this mineral.

It has also been shown that the combination is paralleled to a

remarkable extent in chondrodite and its calcitic matrix.

 

"15th. The 'regular alternation of lamellæ of calcareous and

silicious minerals' (respectively representing the 'intermediate

skeleton' and 'chamber casts') occasionally seen in ophite, and

considered to be a 'fundamental fact' evidencing an organic

arrangement, is proved to be a _mineralogical_ phenomenon by the

fact that a similar alternation occurs in amphiboline-calcitic

marbles, and gneissose rocks.

 

"16th. In order to account for certain _untoward_ difficulties

presented by the configurations forming the 'canal system,' and

the aciculi of the 'nummuline layer'--that is, when they occur as

'_solid bundles_'--or are '_closely packed_'--or '_appear to be

glued together_'--Dr. Carpenter has proposed the theory that the

sarcodic extensions which they are presumed to represent have been

'turned into stone' (a 'silicious mineral') 'by Nature's cunning'

('just as the sarcodic layer on the surface of the shell of living

Foraminifers is formed by the spreading out of _coalesced_ bundles

of the pseudopodia that have emerged from the chamber wall')--'by

a process of chemical substitution _before_ their destruction by

ordinary decomposition.' We showed this quasi-alchymical theory to be

altogether unscientific.

 

"17th. The 'silicious mineral' (serpentine) has been analogued with

those forming the variously-formed casts (in 'glauconite,' etc.)

of recent and fossil Foraminifers. We have shown that the mineral

silicates of Eozoon have no relation whatever to the substances

composing such casts.

 

"18th. Dr. Hunt, in order to account for the serpentine, loganite,

and malacolite, being the presumed in-filling substances of Eozoon,

has conceived the 'novel doctrine,' that such minerals were

_directly_ deposited in the ocean waters in which this 'fossil'

lived. We have gone over all his evidences and arguments without

finding _one_ to be substantiated.

 

"19th. Having investigated the alleged cases of 'chambers' and

'tubes' occurring 'filled with calcite,' and presumed to be 'a

conclusive answer to' our 'objections,' we have shown that there are

the strongest grounds for removing them from the category of reliable

evidences on the side of the organic doctrine. The Tudor specimen has

been shown to be equally unavailable.

 

"20th. The occurrence of the best preserved specimens of Eozoon

Canadense in rocks that are in a '_highly crystalline condition_'

(Dawson) must be accepted as a fact utterly fatal to its organic

origin.

 

"21st. The occurrence of 'eozoonal features' _solely_ in crystalline

or metamorphosed rocks, belonging to the Laurentian, the Lower

Silurian, and the Liassic systems--never in ordinary unaltered

deposits of these and the intermediate systems--must be assumed as