Nascent and melt-crystallized ultrahigh molecular weight polyethylene (PE) have been studied using solid-state C-13 NMR spectroscopy. Significant differences between the two materials are observed in the CPMAS spectra particularly at elevated temperatures. Three separate resonances are observed in nascent samples when the temperature is raised to near the melting point, the third peak being of an intermediate chemical shift between the crystalline and amorphous resonances that are observed in the spectra of melt-crystallized samples. Based on this chemical shift, the third resonance is likely due to polymer chains which undergo conformational averaging which is intermediate between the rigid all-trans crystalline polymer and very mobile amorphous chains. Evidence is reported which shows that this is material that is present in nascent PE below the melting point and is not created during the melting process. These observations are confirmed by the measurement of 2D wide-line separation (WISE) experiments where the H-1 line width of the amorphous component of melt-crystallized PE is much narrower than that of a nascent sample. Numerous nascent PE samples, including those of low molecular weight, display similar spectral features.