...the surface of the Earth was then rather flat and covered by lakes and swamps. The dry land was surrounded by vast swallow seas with fresh water. There were much less mountains and hills and they were not as high... (from a notebook)
An appearance of the prehistoric objects, mentioned in the article, were caused if not by ordinary but very earthly events without any alien interventions.
They are the results of very prosaic activity of people who lived under those conditions and are quite compatible with their possibilities at the time.
Solving the riddles of Maltese and other prehistoric phenomena and leaving the vicious circle of ivory tower reasoning which is removed from reality and often suggests fantastic hypothesis became possible only after applying the new approach to the last stages of geological development, and first of all, to the nature of the relief.