PenMllow.] 
294 
[November 16 , 
I desire to extend my thanks to Mr. J. S. Hiller, Geologist of 
the Assos Expedition, and to Mr. Quincy E. Dickerman, head 
master of the Brimmer School in Boston, for their kind assistance 
in the field exploration of the Marblehead trachyte — work of a 
difficult and disagreeable kind in this case. 
In connection with the preceding, attention may be drawn to 
another point. 
It is well known to those interested in the geology of Eastern 
Massachusetts, that the so-called Norian or Naugus Head series 
was established and held to be the oldest (sic) series of rocks 
in this district, partly because it was said to send intrusive 
masses into all the other formations but was itself cut by none of 
them. It may then be interesting to note, in passing, that the 
writer during the past summer found on Marblehead not only 
granite but also felsite cutting the “Naugus Head” series. A 
well marked felsite dike can be seen on the beach, just west of 
Hr. W. F. Whitney’s boat landing between Fluent’s and Holli- 
ber’s points. While the writer does not assent to the views which 
led to the establishment of the “Naugus Head” series, he points 
to the above facts in order that they may be explained by those 
who believe in that series ; since these facts are diametrically 
opposed to their statements and theories. 
General Meeting. November 16, 1881. 
The President, Mr. S. H. Scijdder, in the chair. Twenty- 
six persons present. 
Mr. Wm. Trelease described the character, and kinds of plant- 
glands, and briefly compared them with those of animals. 
The following paper was read : 
TEMPERATURE OF TREES. 
BY D. P. PENHALLOW. 
In the spring of 1881 observations 1 were made upon the tem- 
perature of Quercus rubra and two specimens of different size, of 
Acer saccharinum. The thermometers used were straight bulb 
1 Made at the Harvard College Botanic Garden. 
