Bulletin of Natural History Society. 67 
Supplementary Note to Article I. 
(23 December, 1890.) 
The writer has lately had opportunity to make a prelimi- 
nary examination of the minute features of the fossil from 
Green Head, described in the above article, and finds it to be 
a protozoon, allied more closely to Oryptozoon than Eozoon. 
The microscopic characters are most easily recognized in the 
earthy (as distinguished from the calcareous) layers, and con- 
sists of minute, branching canals. Under a one-inch objective 
the smaller canals have the appearance of minute threads, 
which run sometimes for a distance of two millimetres with- 
out branching. The larger canals branch more frequently 
and are more sinuous. The canals cross and anastomose with 
each other; they run chiefly at right angles to the axis of the 
fossil, and appear to branch most in going outward from the 
centre. More rarely they ascend from the earthy to the cal- 
careous layer, branching upward. 
The organization of this protozoan was evidently quite dif- 
ferent from Eozoon, where the canals belong to the supple- 
mental or calcareous skeleton; in this species they are rare in 
the calcareous, but abundant in the earthy layers, and are 
chiefly horizontal, while in Eozoon they are represented as 
mostly vertical. I have discovered no trace of the tubulated 
layer of Eozoon in the Acadian fossil. 
Prof. Hall’s description of the canals of Oryptozoon is 
very brief; they are said to run irregularly in all directions, 
and his fossil may have a closer relation to ours than this 
brief description would indicate. Still the mode of growth 
of Oryptozoon is so radically different, that it can hardly be 
of the same genus. I would propose, therefore, for the 
Acadian fossil the name of Archmzoon Acadiense, with the 
following macroscopic characters: 
Animal growing in closely crowded colonies and forming irregu- 
larly cylindrical calcareous columns. The columns are built up of 
alternating layers of calcareous and earthy (silicate) matter, the cal- 
careous layers being usually thicker towards the outside of the column, 
and sometimes failing to cover the whole surface. The layers are more 
or less vaulted, having usually the form of an inverted saucer, though 
often taking the shape of a bluntly pointed cone ; and sometimes they 
are nearly or quite flat. There is often a space between the columns, 
which appears to have been fllled up by a later, irregular growth. 
