Correspondence i 35 
entitled, "Geology of Montmorency," copy enclosed, in the American 
Magazine for November, 1847, by professor Emmons, and he will see 
that neither Logan nor I, but the author of the Taconic system was the 
originator of the faults which Mr. Marcou calls " landslides."' 
Emmons, however, does not appear to have included in his Taconic 
the Montmorency and Charlesbourg shales, but to have regarded them 
as Logan did and as I do, (notwithstanding their great apparent thick- 
ness and high angle of dip to which he refers,) as holding the position of 
the Utica Lorraine, but as being against, not on and much less under the 
limestone as they are represented to be by Mr. Marcou, in his section. 
The article referred to is, it seems to me, of considerable interest and 
importance in view of recent discussions, and I hope the perusal of it 
will induce Mr. Marcou to reconsider the matter and to modif}' his views 
on the subject of the landslides at Montmorency. 
As regards the Taconic it appears to me to be very much on a par with 
the "Quebec group," and like it, will have to be resolved into its ele- 
ments, which seem to consist of parts of all the recognized formations, 
from Pre-Cambrian or Huronian and Laurentian to Lorraine shale. 
Alfred R. C. Selwyn, 
Director tieol. and Nat. History Survey of Canada. 
Charleston and its vicinity continue to be disturbed by earthquake-tre- 
mors. A friend who has spent the winter at Summerville — which town 
it will be remembered is situated nearly over the focus — has shown me 
a record of all notewoithy shocks observed during her stay, from which 
I extract the following. 
1888, Jan, 12. Very severe shock at 10 a. m. The noise was beyond 
description awful, and the house rocked to and fro until I thought it must 
be thrown from its foundations. The furniture in the room continued 
to shake for some minutes after the shock was over. Some of the 
ladies were nauseated hy the shock. 
Jan. 16. A sharp blow under the house at 12.50 and a short shake 
which made the furniture rattle. 
Feb. I. A severe bump under the house with explosion like a gun 
going off, at 10 p. m. this evening. 
Feb. 12. At least a dozen shocks during the past week but all slight, 
though enough to wake one when sleeping. Thunder-storm yesterday 
and three shocks during its continuance. 
Feb. 29. Awakened at 6 a. m. by a severe shock which jarred every 
thing in the room and shook me well up in bed. 
Mar. 2. A severe shock at 11 p. m. The house swayed much and the 
jarring sensation was very disagreeable. 
• This important paper of Dr. Emmons is printed in full from the copy 
sent by Dr. Selwyn. See p. 94. — Ed. 
