DEPARTMENT OF LITHOLOGY AND PHYSICAL GEOLOGY. 153 



ical work of preparing the specimens both for exhibition and storage, 

 has as heretofore been acceptably performed by Mr. Forney. About 

 50 samples of building-stone have been dressed and a large amount of 

 material has been trimmed down into the form of hand specimens for 

 storage exhibition, and exchange. Eleven lots of duplicates, compris- 

 ing some 480 specimens, have been sent out during the year. 



No researches of consequence have been carried on upon Museum ma- 

 terial, excepting so far as was necessary for correct identification, and 

 this has been already referred to. What papers have appeared have 

 been wholly my own and are noticed in the bibliography. 



The numbers given below regardiug the present state of the collec- 

 tion are, so far as they refer to the duplicate collections, mere approxi- 

 mations. A large rock specimen which to-day counts as one, may to- 

 morrow be a dozen or twenty, as it is the custom in many cases to bring 

 in material in the mass, and cut it up or break it, as occasion demands. 



Whole number of specimens in reserve series 18, 000 



Whole number of duplicates 3, 500 



Total 21,500 



Of the reserve series 5,687 are now on exhibition ; of these 2,720 are 

 building-stones, and 1,893 belong to the educational series of rocks and 

 rock-forming minerals. 



