310 APPENDIX 



structure is most easily recognised in the earthy 

 (as distinguished from the calcareous) layers, and 

 consists of minute branching canals. Under a one- 

 inch objective the smaller canals have the appear- 

 ance of minute threads, which run sometimes for a 

 distance of two millimetres without 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 calcareous layer, 

 branching upward." 



In limestone of the Upper Laurentian, near St. 

 John, New Brunswick. 



D. Cryptozoon. 



The description above given of Archaeozoon very 

 naturally leads us to consider the allied Cambrian 

 and pre-Cambrian forms known as Cryptozoon. 



This remarkable and problematical type was first 

 described by Prof. James Hall in the Appendix to 

 his Annual Report of 1882 (No. 26). It is a large 

 massive organism, occurring abundantly on the sur- 



