Where was the garden of Eden?

According to Abdullah Yusuf Ali’s commentary on S2(35) in his translation of the Quran, it was not on earth. 

Quote:Was the Garden of Eden a place on this earth? Obviously not. For, in verse 36 below, it was after the Fall that the sentence was pronounced: "On earth will be your dwelling-place." Before the Fall, we must suppose Man to be on another plane altogether-of felicity, innocence, trust, a spiritual existence, with the negation of enmity, want of faith, and all evil. Unquote

Sura 23

5. We said: "O Adam! dwell thou
And thy wife in the Garden;
And eat of the bountiful things therein
As (where and when) ye will; but approach not this tree,

Or ye run into harm and transgression."

36. Then did Satan make them slip
From the (Garden), and get them out
Of the state (of felicity) in which
They had been. We said:
"Get ye down, all (ye people),
With enmity between yourselves.
On earth will be your dwelling-place
And your means of livelihood—

For a time."

37. Then learnt Adam from his Lord
Words of inspiration, and his Lord
Turned towards him; for He

Is Oft-Returning, Most Merciful.

38. We said: "Get ye down all from here;
And if, as is sure, there comes to you
Guidance from Me, whosoever
Follows My guidance, on them

Shall be no fear, nor shall they grieve.

So mankind is in fact an alien?

This directly contradicts what the Quran says earlier.

In S2(30): 

Behold, thy Lord said to the angels; "I will create
A vicegerent on earth." They said:
"Wilt Thou place therein one who will make
Mischief therein and shed blood?
Whilst we do celebrate 
Thy praises
And glorify Thy holy {name)'!"

He said: "I know what ye know not"

Abdullah Yusuf Ali’s commentary

Quote: It would seem that the angels, though holy and pure. and endued with power from Allah, yet represented only one side of Creation. We may imagine them without passion or emotion, of which the highest flower is love. If man was to be endued with emotions, those emotions could lead him to the highest and drag him to the lowest. The power of will or choosing would have to go with them, in order that man might steer his own bark. This power of will (when used aright) gave him to some extent a mastery over his own fortunes and over nature, thus bringing him nearer to the God-like nature. which has supreme mastery and will. 

We may suppose the angels had no independent wills of their own: their perfection in other ways reflected Allah's perfcction but could not raise them to the dignity of vicegerency. The perfect vicegerent is he who has the power of initiative himself, but whose independent action always reflects perfectly the will of his Principal. The distinction is expressed by Shakespeare (Sonnet 94) in those fine lines: "They are the lords and owners of their faces. Others but stewards of their excellence." 

The angels in their one·sidedness saw only the mischief consequent on the misuse of the emotional nature by man; perhaps they also, being without emotions, did not understand the whole of Allah's nature, which gives and asks for love. In humility and true devotion to Allah, they remonstrate: we must not imagine the least tinge of jealousy, as they are without emotion. This mystery of love being above them, they are told that they do not know, and they acknowledge (in ii. 32) not their fault (for there is no question of fault) but their imperfection of knowledge. At the same time, the matter is brought home to them when the actual capacities of man are shown to them (ii. 31.33). Unquote

References mentioned in his commentary are quoted below:

Sura 2

31. And He taught Adam the nature
Of all things; then He placed them
Before the angels, and said: "Tell Me

The nature of these if ye are right."

32. They said: "Glory to Thee: of knowledge
We have none, save what Thou
Hast taught us: in truth it is Thou

Who art perfect in knowledge and wisdom."

33. He said: "O Adam! tell them
Their natures." When he had told them,
God said: "Did I not tell you
That I know the secrets of heaven
And earth, and I know what ye reveal

And what ye conceal?"

Analysis

The Quran contradicts itself as does Abdullah Yusuf Ali’s commentary. Obviously Adam was in the same place as the angels. This is evident in S2(30)-(36). A few more verses on creation:

S3(59)

The similitude of Jesus
Before God is as that of Adam;
He created him from dust,
Then said to him, "Be":

And he was.

S22(5)

O mankind! if ye have
A doubt about the Resurrection,
(Consider) that We created you
Out of dust, then out of
Sperm, then out of a leech-like
Clot, then out of a morsel
Of flesh, partly formed
And partly unformed, in order
That We may manifest
(Our power) to you;
And We cause whom We will
To rest in the wombs
For an appointed term,
Then do We bring you out
As babes, then (foster you)
That ye may reach your age
Of full strength; and some
Of you are called to die,
And some are sent back
To the feeblest old age,
So that they know nothing
After having known (much),
And (further), thou seest
The earth barren and lifeless,
But when We pour down
Rain on it, it is stirred
(To life), it swells,
And it puts forth every kind

Of beautiful growth (in pairs).

S30(20)

Among His Signs is this,
That He created you
From dust; and then,—
Behold, ye are men

Scattered (far and wide)!

Is there dust where angels live?

Further to the matter, the Quran states in S3(3) He hath revealed unto thee (Muhammad) the Scripture with truth, confirming that which was (revealed) before it, even as He revealed the Torah and the Gospel.

The Quran does not confirm but contradicts the biblcal account. 
Genesis 1
26 And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth. 27 So God created man in his own image, in the image of God created he him; male and female created he them. 28 And God blessed them, and God said unto them, Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth.

Genesis 2

15 And the LORD God took the man, and put him into the garden of Eden to dress it and to keep it.16 And the LORD God commanded the man, saying, Of every tree of the garden thou mayest freely eat:17 But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die.18 And the LORD God said, It is not good that the man should be alone; I will make him an help meet for him.19 And out of the ground the LORD God formed every beast of the field, and every fowl of the air; and brought them unto Adam to see what he would call them: and whatsoever Adam called every living creature, that was the name thereof.

20 And Adam gave names to all cattle, and to the fowl of the air, and to every beast of the field; but for Adam there was not found an help meet for him.21 And the LORD God caused a deep sleep to fall upon Adam, and he slept: and he took one of his ribs, and closed up the flesh instead thereof;22 And the rib, which the LORD God had taken from man, made he a woman, and brought her unto the man.23 And Adam said, This is now bone of my bones, and flesh of my flesh: she shall be called Woman, because she was taken out of Man.24 Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh.25 And they were both naked, the man and his wife, and were not ashamed.