LANCASTER COUNTr. 467 



tlie accumulations of gravel which must have been derived 

 from the regions of the great lakes. 



Besides the ores of iron mentioned, the sulphuret occurs in 

 detached cubic crystals, over a considerable portion of the 

 surface ; galena, or sulphuret of lead, and plumbago, have 

 been found in small quantities ; and chromate of iron and sul- 

 phate of magnesia have been mined in the southern section of 

 the county, for economical purposes; but as we possess no 

 granitic rocks, our list of mineral species is much more meagre 

 than those ol the counties lying more to the east. 



NATURAL HISTORY OF LANCASTER COUNTY. 



In giving a sketch of the Natural History of a single county, 

 in a work of this character, it is of course necessary to com- 

 press the matter as much as possible, as the zoology and botany 

 would separately require volumes equal to the present one in 

 size, were they to be discussed ai some length. Ourcollections 

 have been made more with a view to the Natural History of the 

 commonwealth at large, than to any particular county ; so 

 that no care has been taken to prevent objects collected in 

 other parts of the state from being intermixed with those now 

 under consideration ; whence it has been necessary to omit the 

 mention of some which may have been collected within our 

 borders. 



A note of interrogation has been added to some species to 

 indicate that the species may not be properly named, or may 

 not occur within the boundary of the county. Thus among 

 the fishes, not having been able to examine the trout found in 

 our streams, we quote the name Saimo fontinalis with doubt; 

 and Menopoma Alleghaniensis has been cited with a question, 

 because this reptile has been caught in the Susquehanna some 

 miles above the boundary line of the county. We have in- 

 serted both species of " black-snake," not being certain which 

 of the two occurs with us; but it is not improbable that we 

 have them both. We have seen a green snake in the south-west- 



