1866.] KING AND ROWNET " EOZOONAL ROCK." 191 



structures being merely the product of crystallization, illustrating 

 the " chamber-casts " by a reference to the forms of wavellite, and 

 referring the " proper wall " and " canal system " to tremolite*. 



We succeeded in making a large collection of specimens at the 

 principal " marble- quarries " of Barna-oran, Lisoughter, and Glan- 

 ochan : the latter place yielded the variety we wanted. 



IV. ^' Proper wall " of " Eozoon Canadense." 



Settled quietly before one of Smith and Beck's first-class binocular 

 microscopes, and furnished with the best object-glasses and eye- 

 pieces, we examined a number of specimens, both from Grenville 

 and Connemara, prepared by pohshing and decalcification. While 

 thus engaged the question occurred to us. If, in the laminar portions 

 of Ophite, the layers are the result of superpositional growth, how 

 does it happen that the " proper wall " of the chambers " every- 

 where presents" the tubules which served as passages for the 

 pseudopods ? In this case the under as well as the upper side of a 

 layer of " chambers " must have been tubulated — just, in short, as 

 represented by the transparent section in plate viii. fig. 3 a, b, c, 

 and in the ideal diagram or woodcut in p. 61, of Dr. Carpenter's 

 paper in No. 81 of the ' Quarterly Journal of the Geological Society.' 

 There is no difficulty in conceiving the pseudopods of the exposed 

 or upper " proper wall " of the top layer of " chambers " to play 

 their proper part, as they could be freely protruded through and 

 beyond the orifices of the tubules. But how could those act which 

 belonged to the under " proper wall," considering that their egress 

 would be efi'ectually barred by the upper "proper wall" of the 

 immediately subjacent layer of '^chambers"? The difficulty, we 

 felt persuaded, would be met by the following explanation : — The 

 two layers were separated by vacant spaces, except at certain points 

 or places occupied by " stolons :" in this case the pseudopods of the 

 two layers could be freely thrust through the tubules into the 

 vacancies, where they would be in free communication with the 

 surrounding medium, and also enabled to elaborate the "interme- 

 diate skeleton." But, unfortunately for this explanation, it has 

 been stated that the successive layers of chambers, each having its 

 own proper wall, are often superposed one upon another without the 

 intervention of any "intermediate skeleton" f; also, that "where 

 there is little trace of the intermediate skeleton between the cham- 

 bers, the characteristic structure of the proper wall is still unmis- 

 takeably exhibited "J. 



We next considered that, although it is quite true the " casts of 

 the tubules " are often seen standing apart, they also occur so closely 

 packed together, " standing side by side like the fibres of asbestus," 

 as to forbid the idea that there are any interspaces between them. 

 Again, the tubules must of necessity have had walls. Now if the 



* Professor Harkness has stated his opinion before the Geological Section of the 

 British Association at the Birmingham meeting. See ' Reader,' Sept. 30, 1865. 

 t Carpenter, Quart. Journ. Geol. Soc. vol. xxi. p. 63, pi. ix. fig. 4. 

 I Carpenter, ' Intellectual Observer,' vol. vii. p. 294. 



