Adjective : the scalable slope of a mountain.    From Dictionary.com. 

This was on a high unscalable eminence called Rooi.    From Wordnik.com.  [South Africa and the Transvaal War, Vol. 2 (of 6) From the Commencement of the War to the Battle of Colenso, 15th Dec. 1899] Reference

At its upper end, it was blocked by a wall of unscalable heights.    From Wordnik.com.  [The Yoke A Romance of the Days when the Lord Redeemed the Children of Israel from the Bondage of Egypt] Reference

The city nestled in a hollow between sheer, unscalable black walls.    From Wordnik.com.  [Dwellers in the Mirage] Reference

There are unscalable mountains dividing the river valley from itself.    From Wordnik.com.  [The Dark Design by Philip Jose Farmer] Reference

They are a boundary, a dividing line, a wall impregnable and unscalable.    From Wordnik.com.  [The Night-Born] Reference

The walls were vertical, and to almost all observers appeared unscalable.    From Wordnik.com.  [The First Man in Rome]

Conan's glance sought the unscalable sides of the palace and saw nothing.    From Wordnik.com.  [Conan the Avenger]

Its sides were in parts steep, and unscalable in face of determined resistance.    From Wordnik.com.  [In Clive's Command A Story of the Fight for India] Reference

Digg, for example, is a big unscalable mess that represents a limited viewing set.    From Wordnik.com.  [(RSS vs Search) + (Relevance vs Recency)] Reference

The world is two plateaus separated by a steep, and in some places unscalable, cliff.    From Wordnik.com.  [The Fear of Losing Control] Reference

Its vertical sides seemed unscalable, save where the trail had been cut into the stone.    From Wordnik.com.  [Conan the Wanderer]

Here was a dead and unscalable wall to right and left and in front, and all in deep shadow.    From Wordnik.com.  [Tropic Days] Reference

A valley about 10 miles wide, ending at unscalable mountain cliff, and the river in the middle.    From Wordnik.com.  [The Fabulous Riverboat by Philip Jose Farmer] Reference

It was a narrow cut in the hill, with apparently unscalable sides and open only toward the lake.    From Wordnik.com.  [Ruth Fielding on Cliff Island Or, The Old Hunter's Treasure Box] Reference

I think the site suffered from two main problems; unscalable/expensive hosting and underfunding.    From Wordnik.com.  [Who Wants to Buy a Virtual World?] Reference

The air of superiority worn by the lair people chilled him, seemed to erect an unscalable barrier.    From Wordnik.com.  [Breed to Come]

Have you ever asked your class a question only to be confronted with the unscalable "Wall Of Silence?".    From Wordnik.com.  [Twitter: Ephemeral Learning Tool] Reference

Facing no penalty and no disincentive not to make unscalable mountains out of microscopic molehills, why shouldn't they?.    From Wordnik.com.  [Archive 2008-03-01] Reference

Apparently those who had come through the gate were gathered before those unscalable, unbreachable walls, willing to wait.    From Wordnik.com.  [Web Of The Witch World]

They went on upwards, but it was not possible to reach the crest for a sheet of unscalable vertical cliff barred their way.    From Wordnik.com.  [The Seventh Scroll]

He felt hemmed in by those sheer, unscalable walls, desirous of escape, even if escape meant invading some unknown building.    From Wordnik.com.  [The Bloody Crown of Conan]

This, on the other hand, will essentially try to find ways of making unaffordable and unscalable energy sources a bit less so.    From Wordnik.com.  [US News: “Generation We’s Apollo Project”, Me: “What a dumb idea” « PurpleSlog – Awesomeness & Modesty Meets Sexy] Reference

I told One Bruce and Michelle about you getting stuck on an unscalable site and they both said that Keepers are sent where they're needed.    From Wordnik.com.  [Blood Lines]

For the dramatist, sending his imagination beyond earth to heaven, reserves one peak unscalable in the ascent of man towards the summit of his aspirations.    From Wordnik.com.  [The Growth of English Drama] Reference

The idea of that lonely island, lying at the bottom of an unscalable canyon in the midst of a burning, desolate desert, appealed powerfully to their imaginations.    From Wordnik.com.  [The Boy Inventors' Radio Telephone] Reference

I worry a lot less about India as they seem to have more difficulties for whatever reasons to create their product companies, focusing on unscalable service companies instead.    From Wordnik.com.  [Beware The Reverse Brain Drain To India And China] Reference

Above and beyond him towered the pitiless unscalable rocks.    From Wordnik.com.  [Lucy Maud Montgomery Short Stories, 1896 to 1901] Reference

It was equally unscalable, and much more difficult to undermine or batter down.    From Wordnik.com.  [Andersonville — Volume 1] Reference

To the east of him he knew that there were three miles of almost impassable shore, of unbroken, unscalable cliff.    From Wordnik.com.  [Tomaso's Fortune and Other Stories] Reference

Its two feet of straight depth was unscalable, and when finally discovered the toads were tired of their imprisonment.    From Wordnik.com.  [The Minds and Manners of Wild Animals A Book of Personal Observations] Reference

On the right ran the wall of the stockade, impenetrable and unscalable, and it was a long two miles to the north gate.    From Wordnik.com.  [The Doomsman] Reference

He looked back at the Gerns and saw they were within a hundred feet of the -- for them -- unscalable wall of the stockade.    From Wordnik.com.  [Space Prison] Reference

It was very dark and the forest surrounding the calm expanse of water looked like an impenetrable wall, an unscalable rampart.    From Wordnik.com.  [Black Oxen] Reference

A white man could have found his way only by blind chance through the maze of twisted clefts that seamed the unscalable cliffs and crags.    From Wordnik.com.  [Bloom of Cactus] Reference