to seek return of the properties lost to those tax sales.” Herder Spring, supra at n.15 (quoting Oz Gas at 279). Our High Court agreed that these consequences favor a prospective application of IOGA. We reach the same result when we analyze the Chevron Oil factors on the facts herein. It is beyond cavil that IOGA established a new principle of law as it decided an issue of first impression that was not foreshadowed. In IOGA, our High Court held there is no statutory authority for the taxation of oil and gas beneath the surface. However, at the time of the tax sale herein, the prevailing law in this Commonwealth was that oil, gas, and coal underlying unseated lands were minerals, that they constituted real estate, and were subject to taxation as real estate. F.H. Rockwell & Co., supra (<HOLDING>). The Court in Rockwell reasoned that “tax is
holding provision in oil and gas lease authorizing lessor to use gas for agricultural purposes contained no geographical limitations recognizing oil gas and coal are minerals and holding if oil gas and minerals are reserved from the grant of the surface of several tracts of unseated land  they can be taxed as an estate in land recognizing that a metes and bounds partition when land contains oil and gas results in a serious loss to a coowner who receives a lot without oil or gas under the surface with the loss due solely to the division of the land holding assignment of oil and gas lease is subject to business and commerce code section 2601 holding that allegations that states lease and actions that resulted in taking of oil and gas were sufficient to state claim for inverse condemnation