Generally speaking, because the sea water near the sea surface is exposed to sunlight, it will have a certain temperature, and the further down, the lower the temperature of the seawater.

It is precisely because the temperature of the shallow sea and the deep sea are different, and the pressure and density of the two are also different, so after the sea water reaches a certain depth, this natural boundary of the thermocline will appear.

However, the general thermocline will only appear 100 to 200 meters underwater, or about 500 to 700 meters, and if it appears about 10,000 meters below the water, it may be called a "super" thermocline.

As an immortal cultivator, Xiao Hua naturally knew that there were still many unknown secret realms in this world that had been sealed by Gu Xiu, and there would definitely be many strange creatures in the secret realms, so it was not strange!

But this place has nothing to do with the seal, it is purely a lost prehistoric world, but why can this strange "super thermocline" block its own divine thoughts? Xiao Hua was a little puzzled.

However, Xiao Hua couldn't think too much, this prehistoric megalodon had already swam in front of Xiao Hua, and opened its big mouth, which was full of fangs more than one meter long, and "woo" was a bite.

This megalodon is not a monster or a brute beast, but the bite force of this shark can reach a terrifying more than 20 tons, and if ordinary creatures are bitten by it, they will be seriously injured if they don't die.

Although Xiao Hua is an immortal cultivator and still has a sword and shield on his body, but with a bite force of more than 20 tons, Xiao Hua did not dare to make a hard connection, and as soon as he urged the blister crossing technique on his body, he dragged a long stream of small blisters and flashed above the megalodon.

The megalodon swam forward with a missed blow, and quickly turned around and rushed towards Xiao Hua again, and opened its big mouth, "woo" and another mouthful.

Xiao Hua flashed again, and a series of small blisters appeared on his body again, but this time Xiao Hua did not flash above the megalodon, but flashed under the megalodon, and stretched out a sword from his hand to move forward.

Just listen to "poof", this megalodon, which is more than 20 meters long, was disemboweled by Xiao Hua.

The surrounding water was quickly stained red by the blood of the megalodon, and this megalodon immediately hung sideways in the water, this megalodon is certainly fierce, after all, it is not a monster or a brute beast, and its body is not tough.

Xiao Hua didn't want to kill it, but if he didn't kill the shark, then he wouldn't have time to find the Spirit Gathering Grass, and since the shark wanted to die by himself, then Xiao Hua could only fulfill it.

However, Xiao Hua had just killed this megalodon, and from the dark depths of this forked hole, there were immediately seven or eight more biological breaths that were roughly the same as this megalodon.

"This can't be the Megalodon's lair, is it?"

Xiao Hua was stunned again, don't mess around for a long time This fork hole is full of sharks, isn't it in vain?

Thinking of this, Xiao Hua immediately turned around and returned the same way, since the fork on the left was the nest of the megalodon, then he could only try his luck at the fork on the right.

Sure enough, not long after turning around, Xiao Hua felt that the newly swam megalodon was ferociously eating the megalodon that had just been killed by himself.

This cold-blooded animal is a cold-blooded animal, and without intelligence is without intelligence.

Of course, this is a law of survival in nature, and it is also one of the laws of heaven and earth for all things.

Soon after, Xiao Hua returned to the fork of this submarine cave, he did not hesitate, and urged the "blister crossing technique" on his body to enter the fork on the right.

After seven or eight minutes of walking around the cave, Xiao Hua suddenly noticed that there was a bright light above the water.

Xiao Hua couldn't help but be a little nervous, is this more than 10,000 meters deep at the bottom of the sea, or in a cave, how can there be a bright light? Could it be that this place is really a sealed space where there are demon beasts or other cultivators in it?

Xiao Hua hurriedly used his divine thoughts to carefully scan the surface of the water where the bright light came, but after scanning for a long time, he didn't find any living breath, so Xiao Hua cautiously surfaced.

"Damn, how can this be?".

As soon as he surfaced, Xiao Hua was stunned by the scene in front of him.

The cave on the right was not completely submerged by the sea, and there was a piece of land on one side of the cave that was higher than the water, and there were many plants growing densely on the land, not only flowers and grasses, but also small trees.

In the middle of the plant-filled clearing was a blue spar the size of an egg.

Xiao Hua was overjoyed, and immediately jumped out of the water to the clearing, he didn't care about the blue spar suspended in mid-air, and ran directly to those plants and began to look for the "Gathering Spirit Grass", which was the purpose of his coming here.

Sure enough, the hard work paid off, among these plants, there are not only Juling Grass, but also more than ten plants, and the least medicinal age is two or three thousand years, and the longest one is close to ten thousand years.

Xiao Hua couldn't help but burst into ecstasy, although the Gathering Spirit Dust refined with the Gathering Spirit Grass could only be used to subdue the nest of the group of spirit insects, but the longer the medicinal age of the Gathering Spirit Grass, the more spirit insects could be controlled.

That is to say, the Gathering Spirit Dust refined with the Millennial Spirit Gathering Grass can control thousands of spirit insects at the same time, and the Gathering Spirit Dust refined with the 10,000-year-old Spirit Gathering Grass can control 10,000 worms at the same time.

This is definitely an unexpected surprise, Xiao Hua did not hesitate, took out a brocade box and put away the root of the Gathering Spirit Grass, which was close to 10,000 years old, and also pasted several spirit talismans on the brocade box, which is a good thing.

After harvesting this Gathering Spirit Grass, Xiao Hua carefully inspected the plants in the clearing again, and found another rare elixir "Purple Whisker" that had been extinct in Xiao Lingtian, and the medicinal age was also close to 10,000 years.

It seems that this underwater cave with land has existed for at least tens of thousands of years.

Xiao Hua was very excited, he suddenly discovered that another advantage of being an immortal cultivator is that he can go to places where mortals can't go to explore and hunt for treasures and feel surprised, which is originally a kind of joy of life for immortal cultivators.

After inspecting all the plants, Xiao Hua began to study the blue spar suspended in the clearing.

This blue spar is not large, only the size of an egg, and at first glance, it looks like an unpolished sapphire, but miraculously, this blue gem actually emits a trace of blue light smoke that is visible to the naked eye.

"Wow, what kind of treasure is this?".

Xiao Hua subconsciously took two steps forward, reaching out and wanting to take it.

At this moment, the ground below the gem suddenly flashed with blue light, "buzzing", revealing a hidden circle pattern, and a dark blue transparent barrier immediately appeared around the gem.

"Huh? Actually protected by a magic circle? Hey, that means this thing is a treasure? ”。

Xiao Hua was a little excited, he didn't expect to come to find the spirit gathering grass and encounter treasures, this was really unexpected, but he hadn't stepped on dog shit for a long time, why did this shit luck still exist.