61 



as well as foliate, long and wavy markings associated with the 

 "rod and bead" structures, suggest the fronds of algae. 7. Rarely 

 the "beads" decrease in size in one direction, as in an algal 

 branch. 



Distribution. — Blocks of Salem limestone, with these fossil 

 algae plainly showing on their weathered surfaces, are com- 



Photograph of type specimen in Salem limestone. The differences 

 shown in diameter are due to the position of the camera. 



monly used as side panels, steps, building stone, wall slabs and 

 the like, on public and private edifices throughout the United 

 States. In the city of Washington good exposures may be seen 

 on the entrance steps of the Baptist Memorial Church, located 

 at the N. E. corner of 16th Street and Columbia Road, on the 

 capstones and covering slabs of the garden and lawn walls on 

 16th Street between Allison and Buchanan Streets, on wall 

 panels on the 10th Street side of the Internal Revenue Building, 



