26 XnW VOKK STAHK MTSETM 



\\\t\\ a view to rendering a work on so specialized a subject more 

 intelligible to the general scientific reader and to gather together for 

 reference the data available for the general study of the problem, 

 the opening section of the monograph, consisting of 54 pages, is 

 devoted to a theoretical discussion and explanation of terms. This 

 comprises a brief account of the previous crystallographic work 

 done in connection \\ ith New York calcite occurrences ; a general 

 bibliography of 176 titles covering the crystallographic literature 

 of calcite ; and a short discussion of the mathematical relations and 

 fornuilas fundamental to the study. Under this latter head appears 

 a list of the 313 well-established crystal forms of calcite, including 

 those recorded for the first time in the body of the text, and a list 

 of 115 doubtful or uncertain forms. A gnoironic projection of the 

 above 313 crystal forms constructed on a spherical radius of 7 cm 

 and measuring 100 cm by 90 cm is inclosed in a ix)cket. This has 

 already proved of considerable service in working out the problems 

 connected with the identification and depiction of calcite crystal 

 forms. Tn this portion of the work is also included a diagram bv 

 the use of which the face outline of any crystal form of calcite may 

 be readily drawn and l)y this means a model of it constructed in 

 paper or cardboard. 



The main body of the work is devoted to a detailed description of 

 the calcite crystals comprised in the twenty occurrences discussed. 

 These occurrences are as follows : Rossie, Antwerp, Sommerville, 

 Sterlingbush, Lyon Mountain, Arnold Hill, Mineville, Chilson 

 Lake, Crown Point, Smith's Basin, Glens Falls, Saratoga, Fayette- 

 ville. Union Springs, Howes Cave, South Bethlehem, Xew Balti- 

 more, Catskill, Hudson and Rondout. 



In all about 500 crystals were studied and about one-third of 

 that number were measured. Types, based on crystallographic and 

 genetic differences, are distinguished in the case of most of the 

 occurrences, in one instance (Rondout) as many as nine types 

 being recorded from a single occurrence. Throughout this portion 

 of the work the genetic conditions governing the formation of the 

 various types are discussed and the genetic relations of the types 

 included in each occurrence are studied in some detail. 



The crystallographic combinations discussed in the text are 

 shown in 25 plates and include 136 figures. 



A synoptic table of distribution of forms shows 100 forms 

 recorded on New York calcite, of which 11 are new to calcite. The 

 II new forms do not include those previously recorded by the writer 



