An accumulation of organic matter (living, dead, and decaying organisms), which gives it a darker shade than the soil below it.  Top soil is the most valuable layer of soil.  (Existing Soil Additive, Back Fill)
 
Available in three bulk sizes:
$ 35.00 per Skid Scoop (~ 25 Cu. Ft. or .9 Cu. Yd.)
$ 14.00 per Tractor Scoop (~ 9 Cu. Ft. or .33 Cu. Yd.)
$ 5.00 per 5 Gallon Bucket (~ .66 Cu. Ft.)