and the lamination of acid lavas. 39 
Six years later Dr. Joseph Szab6* expressed the opinion that 
lithophysze were only a stage in the mechanical and chemical 
alteration of spherulites, the bases being removed by chemical 
means, the insoluble particles mechanically, and silica being 
concentrated in the cavity. 
In the same year Karl von Hauert published the analyses 
of four rhyolites and the lithopbysee contained in them, which 
showed that the chemical composition of the lithophyse and 
rhyolites were the same. He therefore held to von Richthofen’s 
view that the cavities were the result of expanding gases, but 
thought that these gases had no metamorphosing action on the 
groundmass of the rock. Later on Justus Rotht adopted 
Szabo’s views and recently repeated them in the second volume 
of his Algemeine und Chemische Geologie. 
Dr. Ferdinand Zirkel§ in 1876 described certain spherulites in 
the rocks from Shoshone Mesa, Idaho, which ‘ have developed 
by decomposition a hollow concentric layer structure.” These 
he considered the same as the lithophysze of von Richthofen 
and that they in like manner were only the result of chemical 
alteration. 
Dr. Ch. E. Weiss| in 1877 suggested that the cavities of hol- 
low spherulites play the same réle as a solid body around which 
a spherulite forms, that the chambered spherulites were 
caused by several gas bubbles being near together when the 
spherulites were developed. 
Mr. Grenville A. J. Cole, in a paper recently published, con- 
cluded that the hollows are due to the decomposition of solid 
spherulites by chemical agents, the material having been car- 
ried out through cracks in the rocks. 
Mr. C. A. Tenne,** in describing the lithophyse in the ob- 
sidian of Cerro de las Navajas, Mexico, says that the substance 
of the lithophysze must be devitrified obsidian, and gives chem- 
ical analyses which show that both have the same chemical 
composition. 
Mr. Whitman Cross,tt in a paper “On the Occurrence of Topaz 
and Garnet in Lithophyse of Rhyolite” points out the fact that 
these minerals are not of secondary formation in the cavities, 
but primary, ‘‘ produced by sublimation or crystallization from 
* “Die Trachyte und Rhyolite der Umgebung von Tokaj.” Jahrb. d. k. k. 
geol. R.-anst., 1886, p. 89. 
+ ‘Die Gesteine mit Lithophysenbildungen von Telki-Banya in Ungarn.” 
Verhandl. d. k. k. geol., R.-anst., 1886, p. 98. 
{ “ Beitrage zur Petrographie der plutonischen Gesteine, 1869, p. 168. 
§ “‘ Microscopical Petrography,” Washington, 1876, p. 212. 
|| ‘* Quarz porphyren aus Thiringen,” Zeitschr. Deutsch. geol. Gesellsch., 1877 
xxix, p. 418. 
“| ‘‘On Hollow Spherulites,” etc. Quart. Journ. Geol. Soc.,.May, 1885. 
** Zeitschr. Deutsch. geol. Gesellsch., 1885, p. 610. 
++ This Journal, June, 1886. 
