24 T. B. Brooks—Lower Silurian rocks 
are well shown. At the Caledonia mine the 1st, 2nd and 8rd 
are well developed, as is also the case southeast of the Keene. 
At this latter pomt the magnesian schist No. 3 is seen in such 
close unc. to the gneiss as to render it probable that beds 
4 e wanting. This could be explained by supposing 
eet Samegulanty in the bottom of the sea in which they were 
e 
Ihe whole series are folded, presenting several anticlinal and 
synclinal axes which run rudely parallel with the edge of the 
Laurentian area, i. e., northeast and southwest. On one sectiona 
half-mile long across the Caledonia and Kearney mines, no less 
than six such axes were observed. Prof. Dana oo - 
rocks of the Potsdam epoch in N ew York as having usual 
gentle dip or as nearly horizontal.” poy neice tote nee Bi not 
embrace the rocks at this locality. e place an outcrop of 
magnesian schist (No. 8) has a dip of 80°, indicating a very 
sharp fold. side from this, the inclinations observed varied 
from 0° to 40°. The upper sandstone has been eroded from 
considerable part of the area about the mines, exposing the 
ower rocks and affording a good st gag for stratigraphical 
study. The surface is quite hilly, the highest point ob- 
served being 120 feet above the valley at its ‘pile 
As has been remar r. Emmons describes formations 
Nos. 1, 2, and 3 in Geology of New York, Part Iv, page 93, 
under the cay tacts names of “ Potsdam Sandstone,” - Specu- 
lar Iron Ore “Serpentine.” He regards the last two as 
well as the Sean which underlies them as eruptive, and 
oes not seem to have observed the sandstone which divides 
the two limestone beds. The planes of bedding were occasion- 
ally obscure in the magnesian rock and sandstones, often so in 
the iron ore and marbles; but taken as a whole they cannot 
uppermost sandstone No. 1, « Potsdam,” as he has re cael 
done, and if he begins the Potsdam epoch at this locality wit 
the bottom of this sandstone, which is unquestionably his inten- 
tion, then the rock beds 2 to 6 inclusive are older than this so- 
called base of the Paleozoic column, This view would 
ibly make them the equivalents of the Taconic system of 
Emmons, and it is strengthened by the similarity in general 
lithological character. number and order of the beds between 
this series and that system as described, in Geology of New 
York, Part Iv, pages 138 to 144. It is hardly to be supposed, 
however, that  Hesane would have passed over so promi- 
nent a suggestion ‘of his favorite system without recognizing it. 
