264 REPORT ON NATIONAL MUSEUM. 



Below is given a list of the more important accessions : 



(1) Ten specimens Vermont marble, showing methods of cutting and 

 polishing. Gift of the Vermont Marble Company. 



(2) Eighty specimens Kansas building stones. Gift of A. A. Robin- 

 son, agent for Atchison, Topeka and Santa F6 Railroad. 



(3) Eighty-two specimens North Carolina building stones. Collected 

 by Prof. W. C. Kerr. 



(4) One hundred and four specimens building stones from the United 

 States and foreign countries. Gift of John S. F. Batchen. 



(5) A collection of thirteen varieties of grindstone. Gift of J. E. 

 Mitchell, Philadelphia. 



(6) Forty-five specimens of Italian marble. Gift of W. W. Story, 

 Florence, Italy. 



(7) One hundred and seventy -five specimens drift and eruptive rocks 

 from Montana. Collected by Dr. C. A. White and J. B. Marcou, TJ. S. 

 Geological Survey. 



(8) One hundred and ninety-four specimens rocks from Yellowstone 

 National Park. Gift of W. H. Holmes. 



(9) Three hundred and eighty-five specimens typical rocks of New 

 Hampshire, being the private collection of the late Dr. George W. Hawes. 



(10) Twenty specimens obsidian and tufa from Mono Lake, California. 

 Collected by I. C. Russell and G. K. Gilbert, U. S. Geological Survey. 



(11) Four large concretions from near the mouth of Cannon Ball 

 River, Dakota. Gift of Brig. Gen. M. C. Meigs. 



(12) Thirty specimens Japanese marble. Received from Centennial 

 Exhibition, Philadelphia. 



(13) Three hundred and fifty-five specimen rocks of Victoria, Aus- 

 tralia. Received from Centennial Exhibition, Philadelphia. 



(14) One hundred and fifty-four specimens building stones of Portu- 

 gal. Received from Centennial Exhibition, Philadelphia. 



(15) A slab of Potomac breccia marble 2x3 feet, from Frederick 

 County, Maryland. Gift of Col. Edward Clarke. 



In arranging and classifying collections, the accurate determination 

 of the specimens is the first essential. For this purpose the microscope 

 is usually employed and some two hundred and fifty thin sections of 

 rocks have been prepared. For exhibition purposes the building stones 

 are dressed into 4-inch cubes, this being the unit size, while specimens 

 of purely lithologic or geologic importance are broken with a hammer 

 into sizes of about 3 inches x 4 inches x 1 inch. 



Specimens illustrative of physical phenomena are prepared to suit indi- 

 vidual cases. In the exhibition series the building stones are clas- 

 sified by States, this method being deemed best calculated to meet the 

 wants of the general public. Collections of lithologic and geologic in- 

 terest, representing the formations of any definite area, or investiga- 

 tions tending towards the solution of any particular problem, are pre- 

 served intact. Miscellaneous collections are broken up and classified 

 by kinds. 



