706 
3. The third notice Gontamed an account of six specimens. of 
pumice obtained in sinking a well near Perote in Mexico. The 
road from Vera Cruz’ to the city of Mexico traverses an extensive 
tract of table-land, 7700 feet above the level of the sea, along the 
foot of the mountains which stretch out from the volcano of Orizaba 
and the Coffre of Perote: The water being exceedingly bad and 
brackish, a well was sunk to obtain better, at a' new inn between 
Perote and Santa Gertrudes. ‘The depth of well was sixty varas, 
the first ten being sunk 'in’sand and the debris of pumice; and the 
remainder in pumice and scoriz intermixed with obsidian.. At the 
depth at which water was obtained the pumice assumed'a more 
compact structure. | | 
