Anthracite and it is found most abundantly in areas that have been subjected to considerable stresses and pressures, such as the flanks of great mountain ranges. Anthracite is associated with strongly deformed sedimentary rocks that were subjected to higher pressures and temperatures (but short of metamorphic conditions) just as bituminous coal is generally associated with less deformed or flat-lying sedimentary rocks. For example, the compressed layers of anthracite that are deep mined in the folded Ridge and Valley Province of the Appalachian Mountains of the Coal Region of East-central Pennsylvania are extensions of the same layers of bituminous coal that are
Anthracite budgerigar mutation the strain and continues to report on its development. Initially found only in Germany, by the end of 2008 descendents of this original mutation had been exported to America, Belgium, Canada, England, Finland, Holland, Italy, Norway, Sweden, Switzerland and Pakistan. The Anthracite mutation has an incompletely dominant relationship with its wild-type allele. That is, it shows a visible effect when present as a single factor (heterozygote or SF) and a different effect when present as a double factor (homozygote or DF). In the green series varieties the SF Anthracite Light Green has one Anthracite allele and one wild-type allele at