35 



tinued during the ages which have elapsed since the 

 consolidation of the granite ; its cause is probably identi- 

 cal with that of the " Brownian movement." On the 

 amount of contraction indicated by the relationship of 

 the volumes of the liquid and gas, the temperature and 

 the pressure have been estimated, at which the consoli- 

 dation of the rock must have been effected. 



26. Pseudo-Organic Forms in Mineral Structures. The 



fact of the partial survival of true organic forms in 

 metamorphic rocks has often misled the lithologist in 

 reference to films and lamellated, radial, cellular, curved 

 or branching structures, of purely crystalline origin. 



a. Supposed Crinoids in thin sections of the meteorite 

 which fell at Knyahynya, Hungary ; under low magni- 

 fying power. Recognized and described by Dr. Otto 

 Hahn in his work "Die Meteorite (chondrite) and ihre 

 Organismen," Tubingen, 1880. Cui*ved crystalline 

 lamellae in a chondrite of the mineral bronzite. 



b. Branching Canals in the supposed gigantic foraminifer, 

 Eozoon canadense, in Laurentian limestone at Cote St. 

 Pierre, Quebec, Canada. The upholders of the organic 

 nature of this structure mainly rely on the resemblance 

 of these serpentine threads in calcite to the canals in the 

 "intermediate skeleton" of the foraminifer, Calcarina. 



c. Structure in Decomposed Menaccanite, resembling that 

 of coral, in diabase of Ilkendorf, Saxony. Alternating 

 lamellae of black menaccanite and white calcium titanite. 



Nos. 25 and 26 are exhibited by Dr. A. A. Julien, of 

 Columbia University. 



27. Suite of Minerals from Elkhorn, Montana. 



a. Silver, two specimens. 



b. Calamine, five specimens. 



c. Smithsonite. 



28. Covellite, Butte, Montana. 



29. Tourmaline, Haddam, Connecticut. 



Nos. 27, 28 and 29 are exhibited by A. Chester Beatty. 



