68 A. CHAMPERNOWNE ON SOME DEVONIAN STROMATOPORID A. 
There is every sign of the Stromatoporoids haying grown in the 
position in which they are now found, and nothing to suggest their 
having travelled. 
They can be followed a few yards from where they come out 
whole, but rapidly become merged in the crystalline rock, and then 
their internal structure becomes obliterated. 
I mentioned above that the fossils sent were chiefly Stromatopo- 
ride. They include also an example of Smithia Hennahi and Helio- 
lites porosus. ‘They are all from the Great Devon Limestone, Dar- 
tington. , 
I will only add that specimens found later than those sent are 
decidedly finer (for they take some weeks to get washed from the 
clay and sandy dolomitic rock in which they are imbedded); and I 
am hoping to get them largely cut and polished, and shall have great 
pleasure in sending some more. 
Discussion. 
Prof. Duncan expressed his belief that many different forms were 
united under the one head of Stromatopora, and that the confusion 
was often due to the mode of mineralization. He cailed attention 
to a Smitha on the table, which, by destructive mineralization, had 
assumed a deceptive resemblance to Stromatopora. He thought 
this had been the case in some of Mr. Lonsdale’s specimens. The 
tubules in the lamine of Stromatopora certainly had much resem- 
blance to the tubules of MWillepora. Some of the specimens on the 
table seemed to have openings like calices; as they opened into the 
coenenchyma they could not be corals. The cross tubules excluded 
them from Polyzoa. They showed no true supplemental skeleton 
or nummuline layer like Hozoon, and so he doubted their Forami- 
niferal character. With regard to the mineralization, he had some 
years before received specimens of fossils from Canada, which Dr. 
Dawson’s description had recalled to his mind. 
Mr. Cuamprrnowne described the tubular structure which he had 
observed in some of the Stromatoporidee from Devonshire, both in 
the horizontal and vertical sections, and felt certain that the group 
contained many different forms. He had never seen Kozoonal struc- 
ture in the Devonshire fossils. 
Dr. Murm stated that some specimens which he had seen re- 
sembled the Hexactinellide, and he thought they represented 
sponges, not precisely Hexactinellids. 
