Ah, yes. The second Oz book. And as such, there are a few inconsistencies with later works.

Beginning with 'The Road to Oz', Baum states that money is not used in Oz, and implies that it has always been the case. Yet here, we have a ferryman demanding money from the travellers before he will take them across the river. Tip, Jack Pumpkinhead, and the Sawhorse have no money, so they have to find another way across.

In addition, greed plays a role in Jinjur's motivations. She intends to strip the Emerald City of all its emeralds so that she and her girl army can buy all the luxuries they wish.

The Wizard plays a crucial role in the disappearance of Ozma. It's a good thing Ozma's a forgiving person, or else the Wizard might have been in trouble two books later when he returned to Oz.

In "The Wizard of Oz," Dorothy and her three friends promise to keep secret the fact that the Wizard is a humbug. But in "Land," both Tip and the Wogglebug express knowledge of this fact. How is this possible? Perhaps Mombi, who knew the Wizard, told Tip about his shortcomings, but how did the Wogglebug find out?

The Thing, also known as the Gump, has palm leaves for wings. Magic or not, this is aerodynamically the dumbest thing a designer could do. The air would go right through with little or no lift! How the heck can this thing get off the ground?

The Crooked Magician from whom Mombi buys her Powder of Life is called Dr. Nikidik in this book and Dr. Pipt if The Patchwork Girl.

Accord to most later Oz books, the Deadly Desert is so deadly that any living being whose flesh touches the sand is instantly reduced to dust. Yet Mombi, Glinda, and the Sawhorse, trample around its southern edge with no ill effects.

According to Patchwork Girl, the Powder of Life is very expensive. If so, why is Mombi wasting some of it on such a dopey test case as Jack Pumpkinhead?

According to the Map of the Lands Surrounding Oz in the front of Rinkitink in Oz, there are no non-fairy countries anywhere in the vicinity. But Tip and his companions manage to reach such a land after a comparitively short flight.

Mombi is very sure of Tip's obedience, particularly when he has already made himself obious as a scamp and a troublemaker! After she's told him she intends to turn him into a marble statue, why on earth doesn't she lock him up?! (Because then he would die and there would go the rest of the series...)

And why doesn't the Scarecrow himself know that all Ozites speak the same language? (Because it would spoil a very cute scene, that's why.)

Where on the Tin Woddsman's chest is there a buttonhole? I don't see where or why a tin man would need buttons.

Ozma is strawberry blond in this book and brunette for the rest of the series.

The Wogglebug has a lousy education if he can't figure out how to count to 17 by twos. There are any number of mathematical possibilities.

I think that's all for now.

I was under the impression that only Mombi actually walks onto the sands of the Deadly Desert, while Glinda and the Sawhorse stop at its edge. Some Oz fans have suggested that since witches are obviously quite different from other people in Oz (they can be melted with water, for example), they may be immune to the power of the Deadly Desert to turn people to sand.
While there may be various ways to count to 17 by twos, it seems to me that the one the Sawhorse suggests in this book of starting at one-half, which actually works to make the pills grant wishes, is an invalid one. Caunting to a number by twos means adding 2 to each number you speak and speaking the result until you reach the desired number. It does not mean multiplying the first number you speak by 2, speaking the result, and then adding 2 to the result and each subsequent number spoken, as the characters do when they count, "One-half, one, three, five, ... seventeen." A more valid method, in my opinion, would have been to start at -1. Then again, why not start at -3, or -5, or...? You can see the dilemma to which this method leads. Maybe the characters could simply have started at 1?

I can't believe I forgot to mention this. Between this book and the last one, Glinda has gotten quite a bit older, grown a few inches, put on some buxom pounds, let her hair go back to its (presumably) natural black, and completely revamped her wardrobe. I wish I knew what epiphany prompted all of this. It might add a whole new level of depth to her character.

And speaking of revamping wardrobes, although Jinjur lists "blowing the royal treasury on a grand shopping spree" as one of her highest reasons for conquering the Emerald City, we never see her once change out of her general's uniform.

"And speaking of revamping wardrobes, although Jinjur lists "blowing the royal treasury on a grand shopping spree" as one of her highest reasons for conquering the Emerald City, we never see her once change out of her general's uniform."

Well, I suppose Jinjur wasn't all that secure in her power, so she felt she had to keep wearing her general's uniform to remind everybody she was in charge.

Of course, the change in Glinda's appearance/wardrobe and the lack of change in Jinjur's can be traced to the artist, John R. Neil, but Nitpickers Don't Deal in Reality.

This was the book that the bizarre animated film "Journey Back To Oz" was based on. I remember Jack Pumpkinhead and the horse (Woodenhead Stallion, he was called in the film, not sure if this is from the book).

Nope. The 'horse' in the book is actually a coincidentally realistic sawhorse (four 'legs', a tail-twig at one end and a chopped-out mouth at the other, knots for eyes).
The Sawhorse he is christened and the Sawhorse he remains for the rest of the series.