20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 66 
visiting the gem and feldspar quarries of Auburn, Topsham, and 
neighboring areas in Maine. While nothing new was secured, he 
was able to add interesting material to the exhibit illustrating the 
character and association of the pegmatite dikes, which is now being 
installed in the \luseum. 
In May Dr. Edgar T. Wherry was detailed by the Museum to 
carry on field studies of certain minerals, rocks, and soils in eastern 
Pennsylvania. Collections of diffusion rings in shale, of glauberite 
crystal cavities in shale, of the rare iron silicate chloropal, and of 
certain soils and the associated rocks, were made. These specimens 
have been added to the Museum collections, and are being inves- 
tigated. Articles on the glauberite cavities and on one group of 
soils have been published. 
In June certain gem and mica localities in New Jersey and south- 
eastern Pennsylvania were visited by Dr. Wherry, and Dr. W. T. 
Schaller of the U. S. Geological Survey. In the course of this trip 
a number of specimens of minerals were obtained for the Museum 
collections. 
HUNTING GRAPTOLITES IN THE APPALACHIAN VAEERY 
The great value of the extinct organisms known as graptolites in 
determining the age of geological formations which contain few 
and often no other kinds of fossils, has been proved time and again. 
During the summer of 1916 Dr, R. S: Bassler and Mr CE: 
Resser, both of the division of paleontology, U.S. National Museum, 
had occasion to test this particular group of fossils in the course 
of a study of the Cambrian and Ordovician shale formations of 
western Maryland. Recent excavations along the Western Mary- 
land Railroad, in the great shale belt just west of Wiaulliamsport 
and extending north and south for hundreds of miles, exposed these 
rocks to such advantage that it was thought possible enough fossils 
could be found in them to determine their exact geologic age and 
structure. However, no fossils of any kind were found after much 
search. It was then decided that the rocks were either barren of 
organic life or the cleavage produced in the strata by the great forces 
resulting in their present folded condition destroyed all traces of 
fossils. 
Finally the fold of black shale shown in figure 25 was observed, 
and at the point marked X, where the cleavage and the bedding 
planes coincided, abundant graptolite remains were discovered. The 
species which were collected proved to be of such typical Trenton 
forms that there could be no doubt of the Middle Ordovician age of 
