Davis. J 16G [Dec. 6, 
black basal ring. All the terminal spines black as well as the sliort rudi- 
mentary processes of rows 1 and 2 on joint 2 on the anterior edge of the 
prothoracic sliield. Tiie spines are all short (^ tlie length of tlie process 
or less) and are partly absent. Only tlie apical one is present on most 
or traces of a few others. The processes are thick, club-shaped, and 
directed slightly baclvward. Rows 1 and 2 on joints 3-5 and 1 on joint 
12 are larger and much thicker than the otliers, possessing the noiliial 
spinulation, partly reduced to black spots. It consists of the apical spine 
and two concentric rows of radiating ones below it. These processes 
have a very narrow black ring at base. Spiracles elliptical, white, 
with a black rim. 
The cocoon is very similar to that of S. Columbia in shape and deci- 
dedly blackish in coloration. 
General Meeting, November 15, 1893. 
Prof. J. S. KiNGSLEY in the chair. Fifty-five persons jiresent. 
Dr. J. Walter Fewkes described the ceremonials of the Mexican 
and Pueblo Indians. 
General Meeting, December 6, 1893. 
President W. H. Niles in the chair. Forty-seven persons 
present. 
The death of Dr, H. A. Hagen was announced. 
Mr. R. E. Dodge gave an account of the geographical 
development of river terraces. 
The following paper was read : — 
FACETTED PEBBLES ON CAPE COD, MASS. 
BY WILLIAM MORRIS DAVIS. 
General occurrence of facetted pebbles on the Cape. — Highland 
Light, North Truro, South Yarmouth, Succonnessett Point- — 
The gravel beds of the Cape were subaerial deposits. — Relation 
of facetting to rock structure. — Postglacial changes of level on 
the Cape. — Evidence afforded by submerged tree stumps, not 
trustworthy. 
The occurrence of facetted pebbles in our gravels was first 
brought to my attention by Mr. J. B. Woodworth, whose general 
account of their distribution is published in the American journal 
