The phrase "lies horizontally" is correct and can be used in written English.
You can use this phrase to describe the position of something. For example: "The picture frame lies horizontally on the shelf."
When he lies horizontally across a queen-size bed, his hind legs hang off the end.
In this photograph – of which there exist a few other versions, each only subtly different from the other – Modotti lies horizontally on a jerga.
There she is, smiling down from the top of the page, with a nice blue rose (appropriating the Socialists' symbol, but changing the colour) that lies horizontally between the words "Marine" and "Présidente".
The ad, two-and-a-half inches high, lies horizontally across the bottom of the front page, below the news articles and a brief summary of some articles in the paper.
"Grant" (1974), the only large piece that lies horizontally on the floor, has nicely colored bands of mauve and ochre around it and an additional, short plank on its dorsal side for formal variety, but it has none of the imposing impact of the stand-up works.
Initially on the right there is a single large inflatable, like a small see-through Li-Lo: which, several inches thick, is for a long while all that separates the two men, as one lies horizontally on top of the other.
When you fall and lie horizontally, more blood (and oxygen) flows to your brain.
A small timber; in architecture, a purlin lying horizontally upon the rafters, Vitr.
Screw caps prevent spills when the opened bottles lie horizontally in refrigerators.
The experimental tests used a mirror arrangement of two portal frames lying horizontally.
He spotted two reels lying horizontally in gray canisters labeled "1960 World Series".
