See quotations.
1821. The stratum, lying immediately under the soil; which throughout a great part of this country is what is here called the hard pan, a very stiff loam, so closely combined, as wholly to prevent the water from passing through it, unless where there are crevices.—T. Dwight, ‘Travels,’ i. 374.
1828. The hard stratum of earth that lies below the soil: called the hard pan.—Webster’s Dict.
1829. The farmer comes to what [is called] hard-pan, a stiff, impenetrable surface, on which no vegetable substance will grow.—H. Murray, ‘North America,’ ii. 273. (N.E.D.)
1839. A soil with a hard pan.—Farmer’s Monthly Visitor, i. 53 (Concord, N.H.).
1842. This [Michigan] soil, which varies in depth from one foot to one hundred, (say the explorers,) is light and friable, but it is based upon something emphatically called “hard pan,” which is supposed to prevent the roots of large trees from striking to a proper depth.—Mrs. Kirkland, ‘Forest Life,’ i. 165.
