20 SMITHSONIAN MISCELLANEOUS COLLECTIONS \'OL. 66 



visitins^" the gem and feldspar ([uarries of Auburn, Topshani, and 

 neighboring" areas in Maine. While nothing' new was secured, he 

 was able to add interesting' material to the exhibit tllustrating the 

 character and association of the pegmatite dikes, which is now being' 

 installed in the Museum. 



In May l^r. 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 ring's 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 .\PPALAC11IAN VALLEY 



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 i(;i6 Dr. R. S. Bassler and Mr. C. E. 

 Resser, both of the division of paleontology, V. vS. National Museum, 

 had occasion to test this particular grou]) of fossils in the course 

 of a studv of the Cambrian and ( )rdovician shale formations of 

 western Maryland. Recent excavations along' the Western Mary- 

 land Railroad, in the great shale belt just west of Williamsport 

 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 ]:)roduced in the strata by the great forces 

 resulting in their present folded condition destroyed all traces of 

 fossils. 



Einally the fold of black shale shown in figure 25 was observed, 

 and at the point marked X, where the cleavage and the l)ed(ling 

 planes coincided, abundant graptolite remains were discovered. The 

 species which were collected proved to be of such ty])ical Trenton 

 forms that there could be no doubt of the Middle ( )rdovician age of 



