Raymond & Narraway : Notes on Ordovician Trilobites 251 



Bumasius trentonensis was figured by Emmons (Geology New York, 

 Report of the Second District, 1842, p. 390, fig. 1) from a specimen 

 obtained from a boulder at Hogansburg, New York. The figure shows 

 a trilobite with a wide, yet defined axial lobe on the thorax, and faint, 

 arcuate dorsal furrows on the cephalon. The original specimen was 

 lost before Hall studied the material for Vol. I, " New York State 

 Paleontology," but Hall figured a plaster cast ot the specimen. 1 Hall's 

 figure differs from that given by Emmons in showing no dorsal furrows 

 on the thorax. Clarke remarks that, as thus figured, it is "an excel- 

 lent Bumastus," while the figure given by Emmons leads one to con- 

 sider it an Illamus. The figure given by Hall corresponds in size 

 and proportions with a Bumasius found in the Trenton Limestone at 

 Ottawa, and which is known to local collectors as Bumastus trenton- 

 ensis. These specimens from Ottawa differ from Hall's figure only in 

 the direction of the dorsal furrows on the cephalon. Hogansburg is 

 just south of the St. Lawrence, 60 miles southeast of Ottawa and only 

 40 miles south of the Ottawa Valley, so that it seems very possible 

 that Emmons' specimen may have come from that region. 



Illcenus trentonensis was the name given by Emmons to a small 

 trilobite figured on the same page of the "Geology of New York" 

 as the species discussed above. Emmons says, in explanation of the 

 figure : 



" No. 3. For this small trilobite, I am indebted to Dr. Crawe, of 

 Watertown. It seems to be rather rare, though it has been found in 

 the Valley of the Mohawk. The specimen from which the drawing 

 was taken was found at Watertown." 



This small Bumastus was taken by Clarke as the type of Bumastus 

 trentonensis. 



If, however, the No. 1 of Emmons' figures is also a Bumastus, as 

 seems probable, the same specific name can not be used for both, and 

 the larger form would be entitled to the name Bumastus trentonensis. 

 To make this transference of names now would lead to endless con- 

 fusion. Since the type of Emmons' No. 1, Bumastus trentonensis is 

 lost, it is not possible to say positively what his species was, and it will 

 simplify matters to follow Clarke in retaining the name for the smaller 

 specimen, and describe the large form under a new name. 



1 The plaster cast of Emmons' specimen is still preserved in the collection of the 

 American Museum of Natural History. 



