GEOLOGICAL MAGAZINE. 
NEW SERIES: “DECADE liz" VOEWeV. 
No. II—FEBRUARY, 1888. 
@l EG sEIN PASE Ake aCe se Se 
BOs 
J.—Note on New Facts rexatine To Eozoon CanapeEnse.! 
By Sir J. Witt1am Dawson, LL.D., F.R.S., etc., ete. 
(PLATE IY.) 
YHE late Dr. Carpenter had undertaken an elaborate series of 
investigations of Hozoon, based on all the material collected 
by myself and others in Canada, with the view of preparing a 
complete and exhaustive memoir on the subject. In consequence of 
this arrangement the new facts obtained for several years have 
remained unpublished. Unhappily the work was left at his lamented 
decease in a very incomplete state. 
The present note is intended, without entering into any contro- 
verted points, to notice some new facts respecting the fossil and its 
state of preservation, which have been disclosed within the few past 
years. 
1. Form of Hozoon Canadense. 
Hitherto this has been regarded as altogether indefinite, and it is 
true that the specimens are often in great confluent masses or sheets, 
the latter often distorted by the lateral pressure which the limestone 
has experienced. The specimen from Tudor, however, figured by 
Sir W. H. Logan in the ‘Quarterly Journal of the Geological | Society,’ 
1867, p. 253, and that described by me in the ~ Proceedings 
of the American Association’ in 1876, and figured in my work 
“ Life’s Dawn on Earth,” gave the idea of a turbinate form more or 
less broad. More recently additional specimens weathered out of 
the limestone of Cote St. Pierre have been obtained by Mr. E. H. 
Hamilton, who collected for me at that place ; and these, on com- 
parison with several less perfect specimens in our collections, have 
established the fact that the normal shape of young and isolated 
specimens of Hozoon Canadense is a broadly-turbinate, funnel-shaped, 
or top-shaped form, sometimes with a depression on the upper surface 
giving it the appearance of the ordinary cup-shaped Mediterranean 
sponges. (See Pl. 1V. Fig. 1.) The photographs exhibited show this 
appearance in two specimens. ‘These specimens also show that 
there is no theca or outer coat either above or below, and that the 
laminee pass outwards without change to the margin of the form, 
where, however, they tend to coalesce by subdividing and bending 
together. The laminz are thickest at the base of the inverted cone, 
and become thinner and closer on ascending, and at the top they 
1 Read at the Meeting of the British Association, Sept. 5, 1887. 
DECADE III.—VOL. V.—NO. II, 4 
