Mr. E. Billings ons ome Lower-Silurian Trilobites. 383 



found chiefly in beds of auriferous quartz of coutemporaneous age 

 with the slates and quartzites composing the mass of the series, 

 which, in Nova Scotia, is 12,000 feet thick; and the auriferous 

 beds are worked, in one district or another, through a vertical space 

 of 6000 feet. Besides auriferous beds of quartz, intercalated beds 

 and true veins are found to yield gold, and are worked. 



A series of sharp and well-defined anticlinals ridge the province 

 of Nova Scotia from east to west, while another series of low broad 

 anticlinals of much later date have a meridional course. At the 

 intersection of these anticlinals the gold-districts are situated, be- 

 cause there denudation has best exposed the upturned edges of the 

 auriferous beds of quartz, and rendered them accessible, sometimes 

 exposing also the underlying gneiss. Plans of Waverley and Shei- 

 brooke gold-districts were exhibited, showing the outcrop of the 

 ed^es of the slates and auriferous beds of quartz in semielliptical 

 forms, with the gneiss at the base of the ellipse. On this ground 

 it was suggested that a correct mapping of the gneisses of Nova 

 Scotia would have an important influence on the development of the 

 mineral resources of the province. 



A plan of some of the lodes in the Waverley gold- district showed 

 the result of operations in 1869, subsequently to the publication of 

 a geological map and sections of the district furnished to the De- 

 partment of Mines by the author in 1868. Citations were made 

 from the annual reports just issued of the Chief Commissioner of 

 Mines and of the Inspector of Mines, confirming the correctness of 

 the author's plans exhibiting the geological structure of Waverley, 

 which is a type of all the Nova Scotian gold- districts. 



May 11, 1870.— Joseph Prestwich, Esq., E.R.S., President, 

 in the Chair. 



The following communications were read : — 



1. " Notes on some specimens of Lower-Silurian Trilobites." By 

 E. Billings, Esq., E.G.S., Palaeontologist of the Geological Survey of 

 Canada. 



(1) The author first described a specimen of Asaphus platyce- 

 johalus, of which not only was the hypostome preserved in situ, but 

 also the remains were more or less well preserved of eight pairs of legs, 

 corresponding with the eight segments of the thorax, to the under- 

 side of which they had been attached. The appendages take their 

 rise close to the central axis of each segment ; and all curve for- 

 wards, and are thus most probably ambulatory rather than natatory 

 feet. They appear to have had four or five articulations in each 

 leg. 



Three small ovate tubercles on the pygidium may perhaps indi- 

 cate the processes by which the respiratory feet were attached. . 



Mr. Billings referred to the large number of Tribolites which have 

 been examined, and expressed his belief that only the most perfectly 



