Br. Dawsoiis ^ Dawn of Life J' 363 



noticed in our paper in the ' Annals & Mag. Nat. Hist.' Oct. 

 1874, vol. xiv. pi. 19. fig. 3 (and equally testified by other 

 veins made known by us*), has originated out of amorphous 

 serpentine, and is formed of (1) incipient chrysotile, (2) true 

 chrysotile, (3) compact acicula?, (4) separated aciculte with 

 calcitic interspaces. In the last condition this vein agrees in 

 every respect with the " cell- wall " in its typical form : it is 

 also in a normal position of parallelism relatively to the adja- 

 cent " chamber and walls," and does not " penetrate diagonally 

 or transversely across" them. 



With regard to the asserted discordancy of direction between 

 the " cell-wall " and chrysotile veins, we may refer to Dawson's 

 figures 1 and 3, pi. viii., which do not seem to be on his sidej 

 and what is equally remarkable is the appearance of there 

 being a strict parallelism between the aciculte of the one and 

 the fibres of the other. But whether these cases are or are not 

 what they appear to be, we cannot but express our belief that 

 Dr. Dawson is acquainted with others in which tliere are layers 

 of chrysotile strictly parallel with the " cell-wall;" otherwise 

 it will be a remarkable circumstance that several cases of the 

 kind have occurred to us. 



Dr. Carpenter some years 'since kindly presented to one 

 of us a thickish slab, 6 inches long and 4| inches wide, of 

 '"''Eozoon^'' beautifully developed both in its laminated and 

 acervuline form. Beneath the laminated portion there is a 

 mass of serpentine which, at the distance of | inch from 

 the eozoonal layers, and 'parallel thereto, is traversed by a 

 vein, I inch thick, of chrysotile in a more or less developed 

 condition. There is no necessity for our dwelling on the 

 parallelism alluded to ; for we have other cases, against whose 

 significancy there cannot be raised any doubt. These consist 

 of thin layers of chrysotile, agreeing in thickness with the 

 adjacent layers of " cell-wall," and which are not only parallel 

 to, but have their fibres in strict parallelism with, the aciculae 

 of the latter. Furthermore, certain of the layers of chrysotile 

 graduate insensibly into " cell- wall " by the conversion of 

 their fibres into separated acicula?, similarly to the cases that 

 have already been published by us. We are prepared, if 

 necessary, to give a representation of this fact also. 



Dr. Dawson avers that our theory of accounting for the 

 eozoonal structures " is chemically extravagant, and that it 

 does not explain the nummuline wall." Passing over the first 

 of these assertions, because it is no more than an echo of the 

 dictum of another authority , with whom only, for obvious reasons, 



• Quart. Journ. Geol. Soc. vol. xxii. pi. xiv. fig. 2; Proc. Roy. Irish 

 Acad. vol. X. pi. xli. figs. 1, 2, pi. xlii. fig. 6. 



