



336 CORRESPONDENCE. 
B Going from Lower Silurian rocks to the clays and gravels 
f the Quaternary Period, which cts nsa them, we find these 
ie resting upon gneiss rocks polished cratched, often with great 
—— as upon a hill in North Sal at Dr. W. Mack's summer 
esidence; in Boston Street in Salem; a dn from Salem towards Lyun, 
on the top of a hill; the scratches all running in a general north-west 
and south-east direction. Among the many igante Danter transported 
Railroad, arise in Chelsea abd: Somerville. At Andover, ages the 
P 1 K i s 
which border the Merrimac, is the celebrated ‘‘horse-back,” called ipeo 
Ridge,"—that puzzle in Quaternary geology. The student of ethnology 
and anthropology can investigate the Indian shell-heaps, or Pena 
meeddings found along the whole coast, containing pieces pottery, 
pe nema dae bones of various animals, especially at ‘et and 
on Plum Island, and many other points, specimens of which are on 
M A in ie Museum of the Peabody Academy of Science. The 
inland zodlogist will eagerly explore the rocks and tidal pools and 
b . 
only by the remains in palæozoic rocks; and the botanist will fin 
the sea-weeds thrown up on the beaches, and in the diatoms of the 
brackish waters, and the meeting of Northern and Southern plants in 
the woods and skirting the coast, much of interest. 
ee 
ANSWERS TO CORRESPONDENTS. 
W.C.G Poughkeepsie. N. Y.— We have often noticed these erosions in the cru 
of the M, Gyrostomum urciolatum Tuckerman, and think ero y are re made Ì by 
the rasping tongue of some Helix or Limax, if not by the larvz o ore 
tera. The d gg pepe removed Pi ed me on — "beneath, is px 
lus of the lichen, and the open papillz 
W. C. P. Sandwich, Maes.— The tetas ou gan May 17) are sae of an apparent! 
undescribed species of Grapholitha, a — d lay p am moth. We had Md 
them May 45th, an abe apple, and a day later perforating the half-expanded le: iid 
flower buds of mei apple, pear and cherry, on which they were very abund: - 
st as the er-worm is 
oe d peie anonn harm, and ai about Mp. se Bow y July 1s 2 fying 
15 3 
ene TEUER i i td d ied ze in the 
is , Tournat of Fobcrering and ond vate Bled by Dr. A. J. Malmgren- recat? 
"refi mem March 90, rta ig London, 
i C. 



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