American Association. 29 
may be compared to Lingula (?) favosa of the Kophyton 
sandstone, but is rounder, and the pitted surface occupies 
less space on the valve. 
Division 2, of the St. John group has remains of several 
genera of seaweeds, among which are two graceful species 
related to Taonurus or Spyrophyton. In the same division 
are layers of fine grained shale, over whose surfaces are 
scattered fragments of the bodies of a small crustacean, with 
a very thin test; this is probably Hymenocaris, as the layers 
have frequent stiletto-like markings, such as the late Mr. J, 
W. Salter has attributed to this genus. 
We now recognize four series of deposits in the Cambrian 
system of North Eastern North America, viz.: Series A, 
The Basal series, the subject of this paper; Series B, The 
St. John Group; Series C, The Georgian (Upper Taconic 
of Emmuns,) Series D, The Potsdam Sandstone. In a 
future article the writer proposes to show the grounds 
which exist for this quadripartite division of the Cambrian 
system in this part of America. 
PROCEEDINGS OF THE AMERICAN ASSOCIATION FOR 
THE ADVANCEMENT OF SCIENCE FOR 1887. 
By T. Westey Mitts, M.A., M.D., 
Professor of Physiology, McGill University, Montreal. 
(Read before the Montreal Natural History Society, October 31.) 
It is proposed in the present communication to give ab- 
stracts of a few of the papers read at the last meeting of the 
American Association, held in New York, and to make 
brief comments on some of them. 
!n the Geological Section, a communication on the action 
of glaciers gave rise to considerable discussion. Its author, 
Dr Spencer, had studied ice action in Norway, and his con- 
clrsions were, therefore, almost entirely the result of per- 
sonal observations. 
Professor Spencer believes that the eroding power of 
glaciers has been much over-estimated. He lays great 
stress on the plastic and flowing nature of glaciers ; they do 
=t 
