CONTRIBUTIONS TO THE FAUNA OF THE CHAZY LIME- 

 STONE ON VALCOUR ISLAND, LAKE CHAMPLAIN 



BY GEORGE H. HUDSON, VICE PRINCIPAL STATE NORMAL AND TRAINING 

 SCHOOL, PLATTSBURG N. Y. 



The following descriptions have been made in order to facilitate the study 

 of a section in the Chazy rocks on Valcour island. All the species were 

 obtained from the beds of this section. 



CYSTOIDEA 

 Genus malocystites Billings 

 Malocystites emmonsi sp. nov. 



Plate I, figures 3-7 



Description. Viewed from above along an axis determined by the 

 point of attachment to the stem and the center of the more globular 

 portion of the theca, and with the food grooves or what I may call 

 the sigma, turned away from the observer, the anus appears to be 

 placed a little to the left and more or less in advance of the summit ; 

 this axis measures from 6 to lo mm. Viewed from the right side, 

 that portion of the theca bearing the rather prominent plates of 

 the sigma is seen to be produced so as to form a distinct and some- 

 what contracted neck with the mouth from 40 to 80 degrees in ad- 

 vance of the distal end of the axis as defined above; the edge of 

 the theca from base to anterior food groove is much flattened form- 

 ing in most cases a rather straight line or chord of from 90 to 140 

 degrees; the posterior edge is also rather straight or but slightly 

 convex, forming a chord of some 45 degrees from base ; from here 

 the outline is usually well rounded to neck under edge of posterior 

 food groove, though some specimens are rather obliquely oval or 

 subovate in outline ; the longest diameter is from base to outer edge 

 of posterior food groove and is from one fifth to one fourth longer 

 than the measured vertical diameter. There are on an average some 

 43 plates in all, not counting the covering pieces, and their outlines 

 usually vary from tetragonal to heptagonal. Some of the specimens 



