Adventures of Roderick Random_ (1748) and The Adventures of Ferdinand Count Fathom (1753) were published anonymously.  Lady Mary was not the only one to attribute Roderick Random to Fielding, and it was actually translated into French in his name.

When Lady Mary heard of Fielding’s death, she expressed deep regret: 

“I am sorry for H. Fielding’s death, not only as I shall read no more of his writings, but I believe he lost more than others, as no man enjoyed life more than he did, though few had less reason to do so, the highest of his preferment being raking in the lowest sinks of vice and misery.  I should think it a nobler and less nauseous employment to be one of the staff-officers that conduct the nocturnal weddings.  His happy constitution (even when he had, with great pains, half demolished it) made him forget everything when he was before a venison pasty, or over a flask of champagne; and I am persuaded he has known more happy moments than any prince upon earth.  His natural spirits gave him rapture with his cook-maid, and cheerfulness when he was fluxing in a garret.  There was a great similitude between his character and that of Sir Richard Steele.  He had the advantage both in learning and, in my opinion, genius:  they both agreed in wanting money in spite of all their friends, and would have wanted it, if their hereditary lands had been as extensive as their imagination; yet each of them was so formed for happiness; it is a pity he was not immortal.”

Writing of imaginative prose literature generally, Lady Mary wrote: 

“The general want of invention which reigns among our writers, inclines me to think it is not the natural growth of our island, which has not sun enough to warm the imagination.  The press is loaded by the servile flock of imitators.  Lord B. [Bolingbroke] would have quoted Horace in this place.  Since I was born, no original has appeared excepting Congreve and Fielding, who would, I believe, have approached nearer to his excellences, if not forced by necessity to publish without correction, and throw many productions into the world he would have thrown into the fire if meat could have been got without money, or money without scribbling.  The greatest virtue, justice, and the most distinguishing prerogative of mankind, writing, when duly executed, do honour to human nature; but when degenerated into trades, are the most contemptible ways of getting bread.  I am sorry not to see any more of Peregrine Pickle’s performances:  I wish you would tell me his name.”

It appears strange that Lady Mary should have been ignorant, when she wrote the above passage in July or August, 1755, of the authorship of Roderick Random, for in January of that year she had evinced an interest in Smollett:  “I am sorry my friend Smollett loses his time in translations; he has certainly a talent for invention, though I think it flags a little in his last work. Don Quixote is a difficult undertaking:  I shall never desire to read any attempt to redress him.  Though I am a mere piddler in the Spanish language, I had rather take pains to understand him in the original than sleep over a stupid translation.”