EOZOON CANADENSE. 535 
behind and downward, then forward and upward, the byssal attach- 
ment soon became enclosed in a wide foramen, this extension ulti- 
mately reaching the umbones of the larval shell to which it unites. 
From these facts it will be seen that it presents not even the re- 
motest resemblance to the Brachiopods, but that the young shell 
has all the proportions of a Bimyarian, and its affinities may be 
quite remote from Ostrea or Pecten. A study of the early stages 
of these last named genera would easily settle all these points. 
Ox Eozoon CANADENSE IN THE CrysTALLINE LIMESTONES OF 
Massacuusetts. By L. S. BURBANK. 
Tue limestone deposits here referred to, occur in the band of 
granitic gneiss which extends in a southwesterly direction from 
near the mouth of the Merrimack river through the.entire breadth 
of the State, and includes the well known mineral localities of 
Bolton, Boxboro’ and Chelmsford. 
Soon after the discovery of Hozoon Canadense by Mr. Bicknell, 
in the serpentine limestone of Newbury, it was also identified by 
Dr. Dawson in specimens collected by me at Chelmsford; as no- 
ticed by Dr. Hunt in the “ American Journal of Science” for Janu- 
ary, 1870. The specimens then examined were not from the rock in 
place, but were obtained from some outlying masses near one of 
the quarries. These discoveries led me to make a further exami- 
nation of several of the old limestone quarries in the same for- 
mation. The eozoonal rock was then found in place at several of 
the quarries, and its position in relation to the other rocks ob- 
served. 
At all the quarries the limestone has been so thoroughly ex- 
hausted, that the limits of its extent at the surface can be readily 
traced. The relations of the limestone to the enclosing rocks can 
thus be easily seen. ` 
By the careful study of these relations, and by reference to 
many specimens collected and facts observed, the following con- 
clusions have been reached. 
1. These limestones are not true stratified rocks laid down with 
the gneiss, but are subsequent deposits of a vein-like character. 
The fact that some of the deposits appear to be interstratified 
with the gneiss, and also are found along a line apparently coin- 
ciding with the strike of the strata, may seem to indicate that 
