91 
[Lane. 
Dr. H. P. Bowditch spoke of certain features of the Zoological 
Garden in Antwerp. He had fdfond that the sale of animals had at 
this garden equalled the loss by death. He £lso said that citizens 
of Antwerp cannot visit the garden unless they are ticket holders, 
by which the Society is able to compel them to become members. 
Professor Putnam called the attention of the Society to the nest 
and e£g shells of a quail found within twenty feet of the Serpent 
Mound. These eggs were hatched on the 19th of September, much 
later than is ordinarily the case. The nest was taken immediately 
after the young left it and the egg-shells were now in their natural 
position ; each egg shell showing how the young quail had cut its 
way out, leaving the larger end attached by a “ hinge” to the rest 
of the shell. 
General Meeting, December 5, 1888. 
The President, Prof. F. W. Putnam, in the chair. 
The following communication was presented : — 
THE GEOLOGY OF N AH ANT. 
BY ALFRED C. LANE. 
[ABSTRACT.] 
N ah ant has as a rocky basis three islets of igneous rock, which 
are connected with each other and the mainland by barrier beaches. 
The main rock of Great Nahant is normally a coarsely granular 
diabase with a granitic structure. Beside a labradorite feldspar 
and augite, the rock contains constantly dark mica and magnetite, 
in microscopic quantity, together with the various minerals known 
as viridite (such as amphibole, chlorite and serpentine), also apatite, 
pyrite, etc. It is well exposed at the foot of Summer Street. 
Opposite Pea Island, we find also a variety containing pseudo- 
morphs of olivine, and at Black Mine a brown hornblende, attended 
by relatively little bastite, forms so much of the rock that it might 
be called a hornblende picrite. This is perhaps the rock sold in 
1690 at three shillings a ton for an iron ore. It is not an inde- 
pendent rock, but merely a local facies. 
The mica appears as one of the later cystallized components, and 
