SECOND REPORT OF THE DIRECTOR I905 



33 



the closed season from December to April has resulted in the short 

 papers, now in press, entitled Contributions from the Mineralogic 

 Laboratory. 



The crystal investigation has, in the main, been confined to de- 

 scriptions of calcite occurrences. The present results have brought 

 out some interesting facts with relation to the connection between 

 crystal habit and genetic conditions. Two new forms were re- 

 corded for calcite and three for datolite. A twinning habit and two 

 clearly marked cleavages were noted for datolite on material from 

 Westfield, Mass., all being new to the species. A unique phase of 

 twinning was noted in the calcite from Howes Cave. 



In addition to the published research, much unpublished work 

 has been done in identifying, comparing and measuring calcite crys- 

 tals from a number of localities. Some experimental work in the 

 artificial production of calcite crystals -has given indifferent re- 

 sults; it is, however, quite evident that this phase of the solution 

 of the crystallo-genetic problem can be, with better methods and 

 apparatus, pushed to a more satisfactory conclusion. 



Collection and field work. The mineral collections have been 

 enriched during the past year by the addition of about 800 speci- 

 mens. These include a fine collection of minerals from the Ster- 

 ling mine at Antwerp, N. Y., a large and complete series from the 

 Chateaugay mines at Lyon Mountain, N. Y., beautiful groups and 

 single crystals of datolite from Westfield, Mass., and some highly 

 interesting groups of calcite crystals from Howes Cave. In the 

 Sterling mine collection are included 19 specimens of millerite, 

 many of them of fine quality; a number of specimens of chalcodite, 

 ankerite and crystallized hematite, and a splendid series illustrat- 

 ing the occurrence and genesis of the iron ore. The Lyon Moun- 

 tain collections, which number nearly 175 specimens, include two 

 masses of amphibole (hornblende) weighing over 50 pounds each 

 and covered with crystals, some of which measure 3 inches in 

 diameter; also a crystal of apatite, which measures 2% inches in 

 diameter and shows penetrating wedges of feldspar which appear 

 to have been driven by some external force into the apatite crys- 

 tal when the latter was in a soft and pasty condition. This is 

 indicated by the "bulge" in the surface around the feldspar 

 wedge, from which it seems that the crystal was already per- 

 fectly formed and had reached considerable dimensions when its 

 deformation took place. The calcite from Lyon Mountain, which 

 is represented by 46 specimens including some excellent material 

 for study, is rich in varied and complex crystals, many of which 



