The Collaborative International Dictionary of English v.0.48:

Marvelously \Mar"vel*ous*ly\, adv.
   In a marvelous manner; wonderfully; strangely.
   [1913 Webster]

WordNet (r) 3.0 (2006):

marvelously
    adv 1: (used as an intensifier) extremely well; "her voice is
           superbly disciplined"; "the colors changed wondrously
           slowly" [syn: wonderfully, wondrous, wondrously,
           superbly, toppingly, marvellously, terrifically,
           marvelously]

Moby Thesaurus II by Grady Ward, 1.0:

73 Moby Thesaurus words for "marvelously":
   abundantly, acutely, amazingly, amply, astonishingly, awesomely,
   beguilingly, bewilderingly, conspicuously, copiously, divinely,
   eminently, emphatically, enigmatically, exceptionally, exquisitely,
   extraordinarily, exuberantly, fabulously, famously, fantastically,
   fascinatingly, generously, glaringly, gloriously, immensely,
   impressively, incomprehensibly, inconceivably, incredibly,
   ineffably, intensely, magically, magnanimously, magnificently,
   markedly, miraculously, nobly, notably, outlandishly, particularly,
   peculiarly, phenomenally, pointedly, preeminently, prodigiously,
   profusely, prominently, pronouncedly, puzzlingly, remarkably,
   richly, sensationally, signally, singularly, splendidly, strangely,
   strikingly, stupendously, superbly, superlatively, surpassingly,
   surprisingly, terrifically, tremendously, uncommonly, unimaginably,
   unspeakably, unusually, wonderfully, wondrous, wondrously,
   worthily