features with respect lo this fossil may be worthy of being placed on record. 

 The specimens from which Mr. Billings described and figm-ed this specicb were 

 either young and imperlectly developed, or else imperfectly preserved. The 

 individuals besides attaining to greater dimensions, possess spines which differ 

 in some respects from those represented. For instance, the spine said to be 

 attached to the eighth thoracic segment, in well developed individuals, attains a 

 total length of some twenty milimetres ; in other words, is almost equal in length 

 to the whole bod}' of the trilohite and has a furrow or groove running throughout 

 its entire length. In a few specimens collected at the Cummings' Bridge deposit, a 

 spine is attached distinctly to the ninth instead of to the eighth thoracic segment 

 as is generally the case. In addition, that spine, which is attached to the 

 occipital or neck segment-i projecting backwards over the six anterior thoracic seg- 

 intnts, and about one-third the length of the other spine, olten exhibits a similar 

 longitudinal groove, whilst these spines often appear quite rounded or cylin- 

 drically attenuated, when completely pyritiaed. These spines, as well 

 as the remaining two attached to the posterior angles ot the cephalic shield, 

 likewise grooved, and also the whole surface of the trilohite, present, under 

 a low power of the microscope, some interesting fVatures. There are minute 

 tubercles scattered over the whole surface of the body and spines ; on the latter 

 they are somewhat larger in dimension. These give an appearance of striation 

 to the spines when looked at with a lens. 



Of the furrows on the glabella, besides the usual two pairs, we have a single 

 one runninsi in a direction transverse to the others. On each side of this furrow 

 two crescent shaped depressions occur, similarly situated on the anterior part of the 

 glabella and i^arallel to the two pairs of furrows. The precise function of these, 

 and their place in the anatomy of the creature, the writer has not as yet been 

 able to ascertain. Another feature about this curious little trilobite is the 

 tubercle or short spine, (akin to those on Triarthrus Becki, Green, when adult) 

 situated about the central portion of the occipital segment, immediately in front 

 of the spine attached to this segment. Further investigation will no doubt 

 determine the precise number of spines this species possessed ; for the present, 

 we are satisfied with stating that it possessed at least more than four spines. 



Orthoceras lamellosum, (YiM). Numerous specimens oi this species occur in 

 the Cummings' Bridge deposit. These were at first referred to the genus £wiioceras 

 of Hall, and the species E. proteiforme ; but after, several perfect detached 

 septa of this species were found showing the positiou of the siphuncle very 

 clearly, as being but very sliahtiy eccentric, its nature as being that of a true 

 Orthoceratite was revealed, only one siphuncle being evident. 



Appended is a list of the fossils which have been found about Ottawa by the 

 writer, and others, the namt-s of whom are given opposite the fo.ssils in the case 

 where the writer has not also lound specimens. In conclusion, my acknowledg- 

 ments are due to Principal Dawson of McGill College, and Mr. J. F. Whiteaves 

 of the Geological Survey, for assistance in naming specimens and for other infor- 

 mation contained in this paper; and my thanks are also due to Mr. C. D. Walcott, 

 of the United States Geological Survey, for a copy of his valuable memoir on the 

 Utica Slate of the United States. 



List of the Fossils found ix the Utica Slate, in the NEiGHBotJRHOOD of Ottawa. 



GENERA AND SPECIES. REFERENCES. 



Ptilodictjaacuta. Hall, 1847, Pal. N.Y., I. p. 74. 



" recta. HaU. Pal. N.Y., I. pi. 26, fig. 1. 



Diplograptus pristis. Hisinger ? ; G. pristis, Hall. 



Climacograptus bicornis. Hall, Pal. N.Y., I. pi. 73, fig. 2. 



Diplograptus mucionatus. Hall, Pal. N.Y., I. pi. 73, fig. 1. 



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