SOUECE OF ST. PETEu's RIVER. 33 



which appear to be very abundantly disseminated through- 

 out the rock.* 



There is in Wheeling a glasshouse, which we visited ; 

 the glass made there is very good ; the sand which they use 

 is brought down from the banks of the Alleghany, and 

 appears to consist of silex nearly pure ; the alkali added is 

 principally unwashed ashes. We were somewhat surprised 

 at hearing, that the clay used in the manufacture of their 

 crucibles was brought from Germany ; indeed we consi- 

 der this very improbable, as a clay very well adapted 

 to this purpose is found in many parts of the country. 

 The atmosphere in the glasshouse was extremely foul, 

 owing to the sulphurous vapour disengaged from the coal. 



The hills in the neighbourhood of the town are covered 

 with masses of clay, sand, &c. which, as soon as they be- 

 come penetrated with moisture, slide along the upper sur- 

 face of the rocks, even where their inclination is but small. 

 This feature is observable only on the northern slopes, the 

 southern are much more abrupt. We were at first induc- 

 ed to attribute it to the effect of the winter frosts, but 

 Colonel M'Ree, who had examined its appearance with 

 care, attributes it principally to the action of moisture, 



•On the banks of the river there were but few shells, and these 

 were referrible principally to the Unio praelongus, (Barnes,) and to 

 the Unio crassus, and Unio purpureas of Say. Among the land uni- 

 valves, Mr. Say observed the following shells, which had been previ- 

 ously described by him ; viz. the Helix albolabris, Helix thyroidea. 

 Helix alternata. Helix palliata, Helix profunda, Helix tridentata, Helix 

 solitaria, Helix inornata. (Vide Nicholson's Cyclopoedia, Amer. Ed. and 

 Journal of the Acad. Nat. Sci. of Philadelphia, Vols. 1 and 2.) 



Vol. I. 5* 



