138 O. A. Derby—Decay of Rocks in Brazil. 
new species. However, the probability is, from the imperfect. — 
nature of the work previously done, that this mineral from 
Maine is identical with the herderite of Haidinger (Phil. Mag., 
iv, 1, 1828, Dana’s Syst. Min., p. 546). Should it prove to be 
otherwise, we suggest the name of Glucinite as appropriate. 
Feeling under obligation to Mr. Perry for furnishing us with 
a supply of specimens for the purposes of this article, we take 
pleasure in here thanking him for his kindness. 
New York, January 3, 1884. 
Art. XX.—WNote on the Decay of Rocks in Brazil; by 
ORVILLE A. DERBY. 
IN examining a collection of specimens from two borings 
made in the coal basin of Arroio dos Ratos, Province of Rio 
Grande do Sul, Brazil, the following observations bearing, 08 
laid by clayey soil, and extends to a depth of 120 meters. Be- 
low that level the shale is sufficiently hard to be called stone, but 
The other boring, 98 meters deep, traverses 20 meters of su- 
perficial sands and clays, terminating below with a gravel bed. — 
