C. D. Walcott — Position of the Olenelhis Fauna. 35 



group of perforated corals. A re-study of all the species and 

 a personal examination of Dr. Hinde's specimens leads me to 

 agree with him that they should be referred to the Actinozoa. 



With the exception of the single doubtful species of Archse- 

 ocyathus, described by Mr. Matthew, from the Paradoxides 

 zone of St. John, 1ST. B., A.f pavonoides, there are no repre- 

 sentatives of this family (Archseocyathinee) in the later Cam- 

 brian. The first true corals met with in the ascending series 

 occur near the base of the Ordovician. 



Echinodermata. — The Echinodermata are represented by a 

 few scattered plates of a species of Cystid, which is referred 

 provisionally to the genus Eocystites. It is impossible to make 

 any comparison between it and the Cystids of the Middle 

 Cambrian. 



Annelida, etc. — The trails, burrows and tracks of animals, 

 that occur in the Lower Cambrian, are nearly all duplicated in 

 the Upper Cambrian. This is true of the genera Planolites, 

 Helminthoidichnites, Scolithus and Cruziana, of the American 

 rocks. As far as determined by traces left by their passage 

 the same type of animals existed throughout the Cambrian. 



Brachiopoda. — The Brachiopoda, with 10 genera and 29 

 s]3ecies, afford a much broader opportunity for comparison, but 

 even here the specific connection is very slight between the 

 two zones. Of the genera, Lingulella is represented in the 

 Paradoxides zone by a group of forms that have received the 

 names L. Lingidoides and L. Dawsoni, in New Brunswick ; 

 Lingulella sp., in Linnarsson's Brachiopoda of the Paradoxides 

 beds of Sweden (Plate III, figs. 24-28), and L. Granvillensis, 

 in the Olenelhis zone of New York. The species of the genus 

 Acrotreta, of the Paradoxides zone of Sweden and New Bruns- 

 wick and the Middle Cambrian zone of the Rocky Mountain 

 Province, are so closely allied to the species from the Olenelhis 

 zone in Nevada that we consider that one species, A. gemma, 

 ranges from the base of the Cambrian through to the Upper 

 Cambrian. Acrothele subsidua also ranges from the Lower 

 Cambrian to the Middle Cambrian, in the Rocky Mountains ; 

 and A. Matthewi, of the Paradoxides zone of New Brunswick, 

 is a closely allied if not indentical species. 



The genus Iphidea has a vertical range from the Olenellus 

 zone in Labrador, to the Middle Cambrian in Sweden, where it 

 is found in the Paradoxides beds. A very closely allied species 

 also occurs in the lower portion of the Cambrian section, in the 

 Grand Canon of Arizona, an horizon that will probably be 

 referred to the Middle Cambrian. 



The genus Kutorgina has one species, K. Labradorica, that 

 has a wide geographic range, and a closely allied representative 

 species, K. Stissingensis, occurs in the Middle Cambrian zone 



