358 F. B. Cowper Reed — A JSfeiv N. American Trilohite. 



In conclusion, one might urge the necessity of closer observations 

 regarding the formation of serpentine from olivine or other anhydrous 

 magnesian silicates. That it is through a process of hydration is 

 self-evident, but as to the conditions under which it goes on 

 literature is strangely silent. Is the process still going on in the 

 exposed masses now open to our inspection, or is it at a standstill? 

 The writer is of the present opinion that both this process and that 

 resulting in the formation of zeolites and chlorites have ceased, so far 

 as material available for study is concerned. They are due to 

 conditions which do not exist on the iunnediate surface, except it 

 may be in such sporadic and unusual occurrences as those of 

 Plombieres, or those more recently described by F. Gounard^ and 

 by Lacroix.^ This paper is, however, written more for the purpose 

 of eliciting the opinions of others than of expressing those of the 

 writer. 



IV. — WooDWAKDiAN MusEUM NoTES r A New Trilobite feoji 

 Mount Stephen, Field, B.C. 



By F. R. Cowper Eeed, M.A., F.G.S. 



AEEPRESENTATIVE collection of fossils from the Middle 

 Cambrian beds of Mount Stephen, Field, British Columbia, 

 has recently been brought back by Mr. S. H. Reynolds, M.A., F.G.S., 

 and presented to the Woodwardian Museum. The fauna has been 

 described by Rominger^ and Walcott^ ; and the latter^ has compared 

 it to that from the Highland range, near Pioche, Nevada, and from 

 near Antelope Spring, Western Utah. The section at Field has been 

 described by Mr. R. G. McConnell.^ 



The collection made by Mr. Reynolds contains the following 

 species : — 



Ogygopsis Khtzi (Rominger) . 



Ogygopsis, sp. 



Biithguriscus Howelli (Walcott). 



Olenoides nevadensis (Meek).'' 



Olenoides cf. quadriceps (Hall & "Whitfield) . ■ 



Ptgchoparia C'ordillene (Rominger). 



Plijchoparia, sp. 



1 Bull, de la Societe Mineralogique de France, vol. v (1882), p. 268. 



2 Comptes Rendus Paris Acad. Sci., vol. xxiii (1896), p. 761. 



^ C. Rominger, " Description of Primordial Fossils from Movmt Stephens, North- 

 West Territory of Canada " : Proc. Acad. Nat. Sci. Philadelphia (1887), p. 12, pi. i. 



* C. D. Walcott, " Camhrian Fossils from Mount Stephens, North-West 

 Territory of Canada": Amer. Journ. Sci., ser. iii, vol. xxxvi (1888), p. 163. 

 " Descriptions of New Genera and Species of Fossils from the Middle Camhrian " : 

 Proc. U.S. Nat. Mus., vol. ii (1889), p. 441. 



5 Correlation Papers, Cambrian : Bull. U.S. Gaol. Surv., No. 81 (1891), pp. 170-1, 

 326-7, 360-1, 366, and pi. ii. 



^ Geol. Surv. Canada, new ser., vol. ii (1886-7), pp. 24d-30d. 



' Matthew (Trans. Roy. Soc. Canada, ser. ii, vol. iii (1897), sect, iv. No. 7, 

 p. 186) contends that Dames' name Dorgpyge (Dames in Richthofen's " China," 

 iv : Beitr. z. Palaont., 1883, p. 23, t. i, figs. 1-6) has the priority of Olenoides. 

 Matthew here describes a variety of Olenoides [Borypyge) quadriceps from the St. John 

 Group of Hastings Cove. 



