The fundamental difference between continental mountains and the oceanic mountains lies in its material. Continental mountains are made essentially by sediments, whereas the oceanic mountains are made of volcanic rocks. Continental mountains were formed by compressional forces, whereas the oceanic mountains were formed by extensional forces. But the common denominator on both mountains are that they have roots to support the mountains. In the case of continental mountains, light-low density material from the mountain is extended down into the earth as a root. In the case of oceanic mountains, there is aso light material supporting the mountain as a root, but in the case of oceanic mountain this material is not light because the composition is light, but it is hot, therefore expanded somewhat. But from the viewpoint of densities, they are doing the same job of supporting the mountains. Therefore, the function of the roots are to support the mountains according to the law of Archimedes. 

          Professor Siaveda described the shape of all mountains whether they are on land or in the sea as being in the shape of a wedge. Could anyone during the time of Prophet Muhammad (sallallahu ‘alaihi wa sallam) have known of the shape of these mountains? Could anyone imagine that the solid massive mountain that he sees before him actually extends deep into the earth and has a root as scientists assure. A large number of geography books when discussing mountains, only describe that part which is on the surface of the earth. This is because they are not written by specialists in geology, but modern science informs us about it and Allah says in the Qur’aan: 
 

And the mountains as pegs. (Qur’aan 78:7).  We asked Professor Sievada whether the mountains have a function in establishing the crust of the earth. He said that this has not yet been discovered and established by scientists. In view of the reply we searched and inquired about this and we found out that many geologists gave the same reply, except for a few.

          Among those few are the authors of thisbook, entitled This book is considered as a basic reference text in many  universities throughout the world. One of the authors of this book is Frank Press. He is   currently the President of the Academy of Sciences in USA. Previously, he was science advisor to former U.S. President Jimmy Carter. What does he say in his book? He illustrates  the mountains in a wedge like shape where the mountain itself is but a small part of the whole  whose root is deeply entrenched in the ground. Dr. Press writes on the functions of  "The Earth". the  mountains and states that they play an important role in stabilizing the crust of the earth. This  is exactly how the Qur’aan described mountains 14 centuries ago. 
Allah said: And the mountains Has He firmly fixed. (Qur’aan 79:32). And He said: And the mountains as pegs. (Qur’aan 78:7).  And said: And he has set up on the earth mountains standing firm, lest it should shake with you. (Qur’aan 16:15). 
          But who could have informed Prophet Muhammad (sallallahu ‘alaihi wa sallam) about this?  We asked Professor Siaveda this question: ‘What is your opinion on what you have seen in the Qur’aan and the Sunnah with regard to the secrets of the Universe, which scientists only discovered now?’  His answer was: I think it seems to me very, very mysterious, almost unbelievable. I really think if what you have said is true, the book is really a very remarkable book, I agree.  Yes, what can scientists say. They cannot attribute the knowledge revealed to Prophet Muhammad (sallallahu ‘alaihi wa sallam) by Allah and contained in the Qur’aan to human beings or to any scientific authority in our times, because all scientists were unaware of all these secrets. Moreover, all the humanity could not have any explanation but to attribute that knowledge to some extra-terrestrial force. Yes, it is a revelation from Allah which he sent to his servant, the unlettered Prophet Muhammad, whom Allah has made an everlasting sign escorting humanity until the Last Hour.