Jhise of the Tiirotiii- or Loircr Cauibria ii. — li'iiichcU. 161 
in part, at least, eonteuiporaneous witli the sandstones." A 
similar case is found in south Wales, where rocks identical in 
all respects with the South mountain rocks have lor some years 
been classed as pre-C^ambrian, having the names Pebidian, l)i- 
metian and Arvonian applied to them, but which now are de- 
clared by Dr. Archibald Geikie to be intrusive witiiin the 
Lower Cambrian.''^ 
Further north, in tl)e line of extension of the gi'cat Alle- 
ghany range, the Canadian geologists have met with similar 
rocks with identical associations. They are described by 
Messrs. Logan, Selw3ni and by R. W. PjIIs, and are unhesitat- 
ingly put into the Taconic. Logan saw so many reasons for 
considering them comparatively recent that he assigned them 
to the old '-Quebec group," which then was considered the 
northward extension of rocks, which in Vermont were called 
■Taconic. The Canadian geologists are agreed on the question 
of the age of these volcanics, and compare them directly with 
the Kevveenawan rocks of the lake Superior region. f In the 
Cambrian of Newfoundland the sections which are given by 
Murray show such rocks as diorites, porphyries and amygda- 
loids. These he puts, with their associated beds, into his 
"intermediate s^^stem," which he supposes is tiie parallel of 
the original Huronian as described by himself and Logan in 
the Canadian rej)orts.;J; 
It is evident, from a survey of the facts from both sides of 
the Atlantic that the Taconic period was liable, from its com- 
mencement to its close, to widespread volcanic action, and its 
strata seem to numifest this fact in the constant interming- 
ling of volcanic rock-material with the ordinary ])roducts of 
sedimentation. AVIiere these events were most fi'e(|uent the 
strata are less fossiliferous. Where they are not legible from 
the strata the sea Avas more fit for life, and in such places fos- 
sils have been found. 
It is also apparent that the oldest sediments which may 
properly be included in the Taconic, above the great plane of 
*Ti'.\i-l!,H)k i.f (irolo-y, :5(l <'(liti(»ii. 1.893, p. 710. 
fLociAN (icoloj-y .)l(JaiiHda. 18<):{, pp. 241-214. 
Ski-wvn. Kcp. Projr. Can. (It'ol. Siir. 1H77-7S, A, pp. :!-]."). 
Ki-i-s. Ilcp. Pnvu'. Can.Geol. Sur., 1880, ,1. p. 2S; jss:. K. p. S.->. 
:tMni{KAY. (Jcol. Sur. Ncwfouiullanil, 18(iS. pp. ll.'>-li;. i{c|)iil)lic;i- 
tiori of ISSl. 
