1886.] NAtURAI, SCIENCES OF 1>HILADEL1>HIA. 351 



Under the circumstances, that is, in view of the microscope 

 showing the admixture of an isometric or amorphous body, this 

 ratio is sufficient to establish the material as a Serpentine. 



Associated with the Serpentine, besides the minerals already 

 mentioned, is a light grayish fibrous mineral. This is composed 

 of Calcite and two Silicates, a silicate decomposable by Hcl 

 (probably equal to the above serpentine), and a silicate insoluble 

 in Hcl, which is probably a pyroxene. Several analyses have 

 been made without establishing the nature satisfactorily. 



On Miocene Fossils from Southern New Jersey. Prof. Heilprtn 

 called attention to a limited collection of fossils from near Bridge- 

 ton and Jericho, Cumberland Co., New Jersey', representing the 

 Miocene formation of that State. The species identified were : 

 Terehra curvilirata, Turritella aequistriata, Turritella Gumher- 

 landia, Trochita centralis, Fissurella Griscomi, Ghama congre- 

 gata, Astarte distans {^indulata), Grassatella mehna, Area cen- 

 tenaria, Nucula obliqua (proxima), Perna maxillata, Pecten 

 Madisonius^ Pecten sp. ? Orbicula luguhris. 



A number of these forms nearly one-half had not been 

 identified in the State before, although fairly abundant in the 

 Miocene tract of the region to the south. They are therefore 

 interesting as bearing directl}^ upon the question of horizon 

 which the scantily-represented Miocene fauna of New Jersey 

 indicates. The speaker stated that in his work, " Contributions 

 to the Tertiary Geology and Paleontology of the United States" 

 (1884), he had suggested that the probable position of the 

 deposits in question would be found to be in the " Marylandian " 

 series Lower Atlantic Miocene a view sustained by the addi- 

 tional fossils that have now been brought to light. 



On the Eelictites of Luray Gave. Dr. Charles S. Dollet 

 remarked that during a recent visit to the celebrated Luray 

 Caverns his attention was called to the peculiar branching stalac- 

 tites known as helictites (e/J?, a spiral), and the question arose as 

 to the method by which a stalactite gives oflF a horizontal branch 

 at right angles ; this branch in its turn perhaps sending out twigs 

 at greater or lesser angles, and at varying degrees of inclination. 



For a better opportunity of studj-ing this interesting phe- 

 nomenon he was permitted to visit in company with Dr. Leidy a 

 chamber seldom opened to inspection, and which, from the deli- 

 cate and fantastic character of its limy deposits, has been called 

 the " Toy Shop." Here the stalactites were found to be of very 

 recent formation, small, hollow, and increasing rapidly. Many 

 branching specimens, or helictites, in all stages of growth, were 

 to be seen. After some time spent in a vain search for an expla- 

 nation of this anomalous structure, he happened to notice two 

 specimens, the incipient branches of which were directed towards 

 each other ; stretched tightly between the branches, and entering 



