230 New York State Museum 



able warrant to be called gastropods, and Stenotheca, 

 too, is probably a pteropod or heteropod. Except for 

 a small, primitive type (Salterella) , cephalopods are 

 missing, and this is a very doubtful form, not accepted 

 by Ulrich and Foerste. The conularids are abundantly 

 represented by the three-sided tubes of Hyolithes 

 Echinoderms are rare but are represented by primi- 

 tive cystoids and crinoids, and remains of sea cucum- 

 bers have been found in the Middle Cambrian (Burgess 

 shales). Worms are abundantly represented by burrows 

 and trails, and in the fine Burgess shale fleshy parts 

 have been preserved as a glistening surface showing 

 fine detail. Sponges were represented by several genera 

 and are somewhat abundant in certain parts of the 

 Cambrian. They are known by their silicious spicules. 

 Jelly fishes occurred and are common fossils in some places, 

 as in the Lower Cambrian of Vermont. Corals or coral- 

 like forms (Archaeocyathidae), which have sometimes 

 been described as corals, again as sponges, were rare 

 in general throughout the period but were locally 

 abundant and in many parts of the world built up lime- 

 stone reefs as in the Lower Cambrian of Inyo county, 

 California. Of the 1500 Cambrian species known from 

 all parts of the world considerably over 1000 have been 

 described from North America alone, and of the total 

 number of species trilobites and brachiopods together 

 make up fully 90 per cent in the proportion of two to 

 one in favor of the trilobites. There are 500 unde- 

 scribed species in the U. S. National Museum, and 100 

 of these will be in print soon, perhaps before the close 

 of 1930 (Ulrich). 



The Lower Cambrian fauna was cosmopolitan in char- 

 acter since the life of this epoch was much the same 



