i 
ous groups low down in the series, and of doubtful age and posi 
tion. The claims of the Cambrian to recognition asa distinet 
he large 
sone have agreed in embracing all the fossiliferous aie 
. 
a new name, which shall not involve us in any Cambrian con 
versies; but, if, as appears from the evidence thus far collec 
we have reached in the lower sandstones of the northwest the 
downward limit of organized existence, we are justified, for the 
present at least, in the use of the term Azoic to designate the 
upon which these sandstones rest unconformably. 
* See Bull. Geol. Soe. [2], viii, 422. 
