196 



0. HoUedahl — Structures like Walcott't 



' ^ Pre-Cambrian Algon- 



in his widely known paper on the 

 kian algal flora. "^' Besides the species of Collenia, which 

 certainly also represent only variations of the stroma- 

 tolite structure, Walcott described a great number of 

 ^^ species" of algae whose beautiful structure and great 

 geologic age have caused no little sensation among geolo- 

 gists. ~ 



From the Newland limestone of the Belt series are 



described no fewer than six new 



Neivlandia, 



Fig. 2. — Two-thirds nat. size. Compare with Newlandia frondosa Wal- 

 cott. 



Camasia, Weedia, Kinneyia, Greysonia, Copperia, the 

 first mentioned with four, the rest with only one species. 



Recently I happened to see several of these types of 

 structures in the Permian limestones of England and 

 should like to draw the attention of American geologists 

 to their occurrence. During a very short stay in New- 

 castle-upon-Tyne in June 1920, my friend Leonard 

 Hawkes, of Armstrong College, who knew of my interest 

 in these peculiar sedimentary structures, arranged an 

 excursion to the Permian magnesian limestone of the 

 Durham district in order to have me see its so-called 



- C. D. Walcott, Smithson. Misc. Coll., 64, No. 2, 1914. 



