ECONOMICAL GEOLOGY. 105 



which cover several thousand acres of land, and are from 

 four to twelve or more feet thick. I have no knowledge 

 in relation to the fertilizing properties of this substance. 

 There is a common impression that muck or mould, from 

 the decay of the leaves and wood, of trees yielding turpen- 

 tine, is not valuable. Its great quantity, however, and its 

 importance, if it can be made available for manure, have 

 led me to some chemical examinations of it. 



The cedar swamp-earth is, in appearance, like the muck 

 from other sources. It is combustible ; when dry, burning 

 with a bright flame, and a good deal of smoke. The 

 amount of ashes left is quite small, only 3.35 per cent, of 

 the dried earth. The following is the analysis of this ash. 



Ash of Cedar Swamp-earth — Analysis. 



Silica 54.427 



Peroxide of iron and alumina, 16.620 



Lime, 11.042 



Magnesia, 3.920 



Potash, 4.249 



Sulphuric acid 3.111 



Phosphoric acid, 5.436 



Chloride of sodium, (Salt), 0.987 



99.792 



An examination was made for nitrogen and ammonia ; 

 but the result obtained was so large, that I have not been 

 willing to publish it, without the trial of another specimen ; 

 and a second specimen sent to me has been lost on the 

 way, so that I cannot now verify it. 



King crabs, or Horse-feet— The Bay-shore of this county 

 is remarkable for the immense numbers of this animal, (the 

 Pblyphemus occidentalis, ov lAmulus -pdlyphemm of the na- 



