6 THE AMERICAN MUSEUM JOURNAL 



opportunity for repeating measurements is not often offered, 

 properly prepared molds of faces provide the ethnologist with a 

 reliable record upon which to base his investigations. 



The task of making the molds from life and preparing the 

 modeled busts for the Museum series was placed in the hands of 

 Mr. Caspar Mayer, under the direction of the curators of the 

 Department of Ethnology Mr. Mayer has greatly improved 

 the old methods and has devised new processes for taking life- 

 masks and utilizing them in connection with photographs and 

 measurements for the rapid production of busts which represent 

 with reasonable accuracv the individuals treated. 



THE COLLECTIONS ILLUSTRATING THE ROCKS AND MINERALS 

 OF MANHATTAN ISLAND. 



HOSE who are; interested in local geology and 

 mineralogy will find much to repay careful study 

 in two collections which are on exhibition in the 

 Museum : the rocks of Manhattan Island at the 

 north end of the Hall of Geology, and the loan col- 

 lection of the New York Mineralogical Club, comprising an 

 almost complete series of the minerals of the island, which is on 

 exhibition in Case 27 in the Morgan Mineral Hall. In addition to 

 the collections on exhibition, there is a large study collection 

 of the rocks which were encountered in the excavation of the 

 Subway. 



The foundation of Manhattan Island consists entirely of 

 crystalline rocks: gneiss, mica, schist, hornblende schist, serpen- 

 tine and magnesian limestone (dolomite). Cutting through the 

 gneiss and schist there are countless veins and dikes of granite 

 and pegmatite, and these have supplied most of the minerals 

 for which the island is noted. The crystalline rocks have been 

 covered with a mantle of Glacial Drift i^unstratified gravel, sand 

 and clay) of varying thickness, while below Fourteenth Street 

 there are extensive river deposits of stratified gravel, sand and 

 clay among bosses of rock (schist) most of which were below the 

 ancient water-level. 



The major portion of the island consists of the gneiss and 



