Doggerland is the floor of the North Sea basin, more properly the southern end of the North Sea. It is named after the Dogger Bank, a shallow region that was formerly an Ice Age moraine. It was probably an island for a time. Alfred de Grazia's web site has a couple of posts on this region see www.q-mag.org/doggerland/index.html and www.q-mag.org/thegreatplainofa/index.html
The latter post is based on a book by Frenchman Jean Deruelle, and this claims Doggerland was once the great plain of Atlantis, and the Dogger Bank where the great city lay. It should be noted this book appeared before geologists and others became interested in the sea floor mapping by oil and gas extraction companies. Robert Graves, it is said, toyed with the idea of placing Atlantis on the Dogger Bank, and Jurgen Spanuth, in Atlantis of the North (Sidgwick and Jackson:1979) claimed it was an extension of Heligoland, just off the German coast.
The submergence of Doggerland has been dated by the Dutch at somewhere between 6200-5500BC, which more or less pans out to the same time that the Mesolithic boatyard beneath Boldner Cliff in the Solent was drowned, or further afield, the swamping of Sundaland in SE Asia (leaving as remnants the islands of Indonesia). What Deruelle did, as he required to identify the megalithic people with the Atlanteans, was to suggest the sea level calculations of the Dutch was in some way faulty, and Doggerland was drowned closer to 3000BC. This is remarkably similar to Paul Dunbavin in his book, The Atlantic Researches, Nottingham:1995, but he visualised the plain as the floor of the Irish Sea, in contrast. Deruelle pointed out that the land is able to rise and sink and this was not part of the calculations – requiring a much later date. Not only that, he pointed out that the event is currently 19m below the surface of the modern Netherlands which implies the land has subsided by that amount. He developed a series of maps that showed Scotland and Sweden rising up as a result of rebound after having the weight of the ice removed but the floor of the North Sea, instead, had subsided (as in the case of southern Britain as a whole).