The Memoirs of Dolly Morton (1899) for anyone interested, is fairly typical of the erotic novels of the day, being a narrative recounted as "true" (cf. Moll Flanders (1722)), and with a good deal of historical detail. The focus on history helped it pass muster as literature rather than pornography; likewise, a substantial part of the book focuses on flagellation, which was considered curiosa but not necessarily obscene - sadism and masochism being still in the process of being defined in both the popular consciousness and the burgeoning field of medicine and psychology.

There are a few errors regarding dates and the like. For example, the beginning of the novel relates events in 1866, and the narrator is having a discussion with a former slave named Mary who was enslaved for twenty-five years, and relates:

"I got my fust whippin' when I was 'bout seven years old, an' I got my las' one when I was twenty-five years old; only a week 'fore we was all set free by de President ob de United States."

Which, if you do the math would have the Emancipation Proclamation in 1861 (the start of the American Civil War), rather than 1863 (when it was given) or 1865 (when the war was over and slaves would generally have been free in practical as well as legal terms). This confusion of dates is sort of endemic to the novel, as we'll see.

Many of the specifics, as near as I can judge, are generally accurate but shaded toward areas of prurient interest and stereotypes of the day. For instance, the various accounts of whippings (birching, paddling, etc.) seem to owe more to popular flagellation literature like The Merry Order of St. Bridget (1857). For example, compare this account by former slave Andrew Boone [PDF]:

Dey whupped me wid de cat o’ nine tails. It had nine lashes on it. Some of de slaves wus whupped wid a cobbin paddle. Dey had forty holes in ‘em an’ when you wus buckled to a barrel dey hit your naked flesh wid de paddle an’ every whur dere wus a hole in de paddle it drawed a blister. When de whuppin’ wid de paddle wus over, dey took de cat o’ nine tails an’ busted de blisters. By dis time de blood sometimes would be runnin’ down dere heels. Den de next thing was a wash in salt water strong enough to hold up an egg. Slaves wus punished dat way fer runnin’ away an’ sich.

With an account from Dolly Morton:

"When I was a little girl I used to get spanked; when I grew big, dey whipped me on de bare back or bottom wid de strap or de hick'ry switch; and I'se had de paddle on my bottom several times," said Mary, coolly as possible.

"Who used to whip the women?"

"One ob de overseers gener'ly; but sometimes de Massa himself used to whip de house-servants, Dere was a room kep' for de purpose, an' when a gal or a woman was whipped, she was tied face downwards on a long bench, den her close was turned up an' she got her allowance."

"Were the whippings severe?"

"Oh, dey always hurt us dreffully an' made us squeal out loud an' wriggle; an' sometimes we was whipped till the blood come."

So, same basic concepts, but the fictional narrative plays a bit more toward erotic flagellation. Similar poetic licence is taken in various other details, for example the "trial" and "sentencing" when Dolly and her partner are found to have been helping runaway slaves in Virginia is much quicker and more fantastic than could realistically be expected, and the sentence of corporal punishment is an unlikely verdict, except to feed the propensities of the novel.

Dolly Morton's part of the narrative begins properly in 1859, noting:

Towards the close of the year, the North was startled by the execution, or, as we called it, the murder of the great abolitionist, John Brown, at Harper's Ferry.

Brown was actually hanged in Charles Town some weeks after his raid on Harper's Ferry; the exact timeline of events is foggy, but Chapter 16 begins:

I will now pass over a period of four months. During that time, events had been marching rapidly and stirring things had happened. The slave States had seceded from the Union. Jeff Davis had been elected president of the Southern Confederacy. Fort Sumter had been taken, and the war had begun.

Secession was declared in December 1860, Davis was elected president in February 1861, and the first battle of Fort Sumter was in April - so far, so good.

For some time past, business in the State had been almost at a standstill. Therefore Randolph could not dispose of his cotton, which had accumulated in the sheds which were full to overflowing. He was a rich man, but most of his income was derived from the sale of his cotton, and, now that there was no market for it -while, at the same time, the great expenses in keeping up the plantation were going on he became very much pressed for ready money.

The Union blockade was declared by Lincoln in April 1861 in his Proclamation of Blockade Against Southern Ports, but it took time to go into effect with the organization and equipping of the fleet and just getting ships into position; the timeline isn't clear so it's not certain how long it took for plantation owners in Virginia to feel the "pinch."

All his friends either had left the State or had joined the Confederate Army. He would have done so himself except that he was too old to go as a private soldier and he was unable to get a commission as an officer, owing to his having no knowledge of military affairs. But he had been elected member of Congress for the Southern Confederacy.

Narrative license aside, this is tricky to adjudicate historically - the Provisional Army of the Confederate States was formed in April 1861, and ages for enlistment varied from state to state. The lack of military expertise wasn't a showstopper to getting a commission in the Confederacy. Major plantation owners were generally exempt from military service under the "Twenty Slave Law" part of the Second Conscription Act, but that wasn't passed until October 1862.

Mention of Confederate currency is not given, but there is a note on the price of slaves:

Since the breaking out of the war, several of the field hands had run away and had managed to get clear off, although the "underground stations" had been closed. Randolph had offered two hundred dollars reward for the capture of each runaway, but not one of them had been brought back. These losses had vexed him very much, the runaways having been some of his strongest and finest young men and women, each of whom was worth from fifteen-hundred to two thousand dollars.

These prices seem to be in Confederate dollars, and generally match the increased price of slaves in Virginia in the early part of the war in Crucible of the Civil War: Virginia from Secession to Commemoration.

The weeks passed, and, in their course, the tide of war flowed nearer to us at Woodlands. The Federal troops had entered Virginia, and many skirmishes had taken place with various results. Then came the battle of Bull Run, in which, as you know, the Federals were utterly defeated. When the news of the Confederate victory arrived at Woodlands, Randolph was jubilant.

First Battle of Bull Run was in July 1861, so we're still very close to the beginning of the war, and the sparse details are essentially correct (Union Army crossed into Virginia, soundly defeated).

A short time after the battle of Bull Run, Randolph was summoned to Richmond to attend the first meeting of the Congress of the Confederates States.

The First Congress of the Confederate States was convened in November 1861.

Fighting was always going on somewhere. The Federal troops were concentrating in force, and were pressing on Richmond. Many of the neighbouring plantations had been occupied by parties of the union soldiers, and I was daily expecting them to make their appearance at Woodlands.

Virginia features prominently in the Eastern Theater of the American Civil War, but is hard to judge - McClellan's troops crossed the Ohio River into Virginia in May 1861 and dominated the northwestern part of the state, so it's fairly accurate so far. The book mentions "Captain Franklin had been campaigning in a very rough way for six months," which suggests he'd been either training in camp or in the field for that period.

I may as well here tell you that I never saw my soldier-lover again. He was killed a year later in the battle of Cedar Mountain.

The Battle of Cedar Mountain took place in August 1862, which doesn't quite jive with "a year later."

Content warning: The slavery talk grows increasingly dire and graphic as the post goes on, with discussions of sexual violence and a period depiction of an enslaved eighteen year old being whipped.

/u/AncientHistory ably relieved me of any need to go into the military details, so let's talk Underground Railroad and slavery. The UR as depicted, mostly by implication, in Dolly Morton looks like the same one that existed in the original historiography of the subject. The author even cites the dean of first-generation UR historians, Wilbur Siebert.

Siebert did his homework, going over newspapers, sending out questionnaires, and devoting a large portion of his life to the work. He believed the UR didn't quite have stable personnel and efforts to facilitate escapes varied over the decades,

but overall he presented a portrait of a highly organized system involving thousands of northern agents and a "great and intricate network" of stations leading to Canada. He reinforced this image with detailed maps (largely a product of his vivid imagination) that looked very much like contemporary railroad maps.

That's a fascinating picture and probably still the pop culture understanding of the system. Siebert's railroad activists are usually white men, but they probably wouldn't have served the expected market for the novel too well as protagonists. Besides that, it's uncannily up to date with contemporary scholarship. Siebert published the year before Dolly Morton hit the shelves. The author is also on firm ground in placing women in the antislavery movement -it was notorious among its enemies for being full of ladies-, making one a Quaker, and citing their initial activities in Philadelphia, which had large Quaker and free black communities that made it their business to help fugitives along, the most famous of whom may be Ona Judge. George Washington brought her to town during his presidency. She took things from there.

So that's the good. Here's the messy.

Siebert's work was taken as definitive into the early Sixties, when Larry Gara basically burned it down. It turned out that Siebert conflated occasional helpers with diehard abolitionists and was a bit of a sucker for anything the latter told him about their glory days. The new consensus became that most fugitive slaves helped themselves, with incidental help from white antislavery people until they hit the North. There was no national network, but rather a set of ad hoc committees and individuals.

Of course now we have some pushback against Gara and the consensus seems to be in the muddle. Networks do exist, but intermittently -running out of cash was a problem- and only on a local scale. The program would be less one of getting a person to Canada than getting them to the next point of refuge or transferring them to the nearest known separate operation. An actual "station," such as they were, in the South is unlikely, but a few individuals at least in the Border South made attempts at it. They were usually one-person affairs near to or in major point of egress, like a port. So if we restrict the Underground Railroad to that scale, which is about all the book depicts for narrative reasons, that part holds up fairly well.

A Yankee, or two Yankee women, involved in such work would raise suspicions quickly. Any strange white person might be meddling with the enslaved and putting ideas in their heads about how they really shouldn't like slavery. Attacks on such people are a feature of times of stress or perceived danger to slavery's integrity. They might be dealt with how the ladies in the novel were. It's unlikely in the extreme that white women would be whipped, especially in a semi-public setting (what their husbands and fathers might do in private, I can't really say), but lynch mobs were the preferred way to deal with the abolitionist menace and so far as it goes, the book follows about the normal procedure I've seen elsewhere.

The victims are taken out and interrogated, which sometimes grows into a full "trial" with appointed lawyers who may actually have legal credentials. (Not that the trial would adhere to legal norms, of course.) Public whipping, tar and feathering, and riding on rails are normal ordeals, as is the business about giving the victims 48 hours to leave town or face worse. Additionally victims might have their heads shaved or half-shaved, be marked on their faces, and even "sold" at mock auction. Details vary, but all of this could have taken place in western Missouri or Bleeding Kansas as easily as Virginia (perhaps more so, given frontier areas tend to be rougher about such things). So excepting that the victims are women and their ordeal is written to titillate, that part holds up pretty well.

And now we're into the really awful stuff. The novel has a frank discussion of sexual violence against enslaved women. That's very much a thing, to the point where there's a steady trade in "fancy" slaves bought specifically to be raped. Beyond that, there's plenty of evidence that enslaved women who just happened to be on hand were preyed upon by their enslavers, sons of the same, and/or overseers. Definitely a thing, and a staple of antislavery literature.

There's also a scene where an enslaved girl, about seven, is whipped. Whipping a slave that young is always possible, but she may have been a little younger than usual to start in with such punishment. However, her ordeal and pleading for it to stop remind me strongly of an occasion in Frederick Law Olmsted's A Journey in the Backcountry. There an eighteen year old is caught away from her assigned task without leave and, this is pretty bad:

“That won’t do,” said he [the overseer], “get down on your knees.” The girl knelt on the ground; he got off his horse, and holding him with his left hand, struck her thirty or forty blows across the shoulders with his tough, flexible, “raw-hide” whip. They were well laid on, as a boatswain would thrash a skulking sailor, or as some people flog a baulking horse, but with no appearance of angry excitement on the part of the overseer. At every stroke the girl winced, and exclaimed, “Yes, sir!” or “Ah, sir!” or “Please, sir!” not groaning or screaming. At length he stopped and said, “Now tell me the truth.” The girl repeated the same story. “You have not got enough yet,” said he, “pull up your clothes-lie down.” The girl without any hesitation, without a word or look of remonstrance or entreaty, drew closely all her garments under her shoulders, and lay down upon the ground with her face toward the overseer, who continued to flog her with the rawhide, across her naked loins and thigh, with as much strength as before. She now shrunk away form him, not rising, but writhing, groveling, and screaming, “Oh, don’t, sir! oh, please stop, master! please, sir! please, sir! oh, that’s enough, master! oh, Lord! oh, master, master! oh, God, master, do stop! oh, God, master! oh, God, master!”

It's possible that the author of Dolly Morton came the whipping scene independently, but he either read Siebert or had a good idea of what he said so there may be some real research involved. Olmsted's travelogues of the South were prominent works in the 1850s, though I'm not sure of their European reach. They're the kind of book you'd expect someone at the time looking into the late antebellum to have dug up, especially since the first modern history of slavery is still in the future at the time of writing.

Overall, it looks like the novel is the work of someone who did at least some of their homework. It's obviously not intended as a history proper, but there are clear signs of familiarity with the the-current literature. Though there are bloopers -I'm not sure where they're getting cotton grown in Virginia, for one- and improbabilities, it actually held up much better than I expected.

Sources

Bleeding Kansas: Contested Liberty in the Civil War Era by Nichole Etcheson (Missourian lynching examples)

Gateway to Freedom by Eric Foner (underground railroad historiography)

Road to Disunion (2 vols) by William Freehling (more lynch mob examples)

River of Dark Dreams and Soul By Soul by Walter Johnson (fancy slaves and sexual abuse)