124 Scientific Intelligence. 
the principal classes of mineral springs, thermal and of ordinary tem- 
perature, and comprehended under the terms acidulous, saline, sulphu- 
retted and chalybeate, Prof. R. entered into a particular account, 
logical and chemical, of two very distinct classes of springs of fre- 
springs which occur belong to the former of the two classes, Such, 
for example, are the celebrated Alum springs and Brinkley’s springs 
pores of the slate with this substance, which, in virtue of its large ex- 
cess, would have power to decompose the sulphuret of sodium, and per- 
haps other salts present, and thus give origin to the smal] amount of 
carbonate of soda, which imparts alkalinity to these waters, The great 
proportion of silica, in the solid residuum of these springs, may doubt- 
less be ascribed to the solvent power of the alkaline carbonate. 
3. On Reptilian foot-marks in the gorge of the Sharp Mountain near 
Pottsville, Pa. ; by Isaac Lea, (Proc. Amer. Phil. Soc., 1849, p. 91-) 
—The object of this communication is to announce to the Society, that 
cps Fi i dape’ 
