395 



This species varies greatly in the elevation. In some the height is only 

 about one-half the width of the base, while in others the height and width 

 are equal, with every intermediate stage. 



Locality and Formation. Montreal ; Chazy limestone. 



Collector. T. C. Weston. 



11. Species from the Quebec Group, published in 1860. 



In order that descriptions of all the species of trilobites of the Ldvis 

 formation may appear in this volume, it is thought advisable to republish 

 those described in the Canadian Naturalist and Geologist. This will be 

 found to be convenient for those who may not have access to the volumes 

 of that journal. 



{From, the Canadian Naturalist and Geologist, vol. v, August 1860.) 



" On examining the specimens recently collected at this locality (Point 

 L6vis), I find some evidence of several groups of species, each occurring in 

 a rock somewhat different in appearance from that which contains the 

 others. It does not seem improbable, judging from the fact that all the 

 three varieties of limestone occur in close proximity to each other, that 

 these species may yet be found more or less intermingled in the same beds, 

 but for the present it is best to keep them separate. I shall designate the 

 rocks simply as limestones Nos. 1, 2, 3, and 4." 



The genera collected in each are as follows : 



The species were collected by Sir W. E. Logan, the late John Head, 

 Esq., Dr. T. S. Hunt, Prof. R. Bell, and J. Richardson. To save space 

 I shall not repeat the locality and formation after each description. 



AGNOSTUS AMERICANUS, (N. sp.) 



+ 



Fig. 372. Fig. 373. Fig. 374. 



Fig. 372. Agnostus Americanus ; a, the tail ; 6, the head ? Both a little magnified. 



Fig. 373. Agnostus Orion. Natural size. 



Fig. 374. Agnostus Canadensis ; a, the tail ; b, the head ? Both magnified. 



NOTE. All the figures in this article are of the natural size, unless otherwise specified. 



