No. 161.] 
95 
Page, 
Salt from sea water. Suggested improvement in manu- 
facture, 87 
Erratic blocks. Economical uses, 87 
Important facts in their distribution, 88 
Tertiary clays of Suffolk county, 89 
Economical uses of these clays. Kinds of clay, 89 
Occur abundantly on Long-Island, . « . 89 
Undulating strata. Too deep for use in some places,.. 90 
Lignite of the clays and associated beds, 90 
Shells, 00 
Uses of these shells, .... 90 
Importance of noticing the occurrence of shells buried 
in the earth, 90 
Pyrites often mistaken for gold; and its uses, 91 
>^ti>te Museun) of Natural History, 91 
