Portal Tombs are probably the most dramatic and easiest of the Irish Tombsto identify. They are a direct development from the earlier Court Tomb. They usually consist of two tall matched upright stones known as Portal Stones, two side stones and a low back stone. These formed a single rectangular chamber which was topped with a large capstone(s). The Portal stones were deliberately taller than the back stone so that the top or underside of the capstone would form a certain angle. In some cases chocking-stones were placed between the capstone and the back stone to achieve the desired angle. At many of the tombs a door stone was placed between the portal stones. The chamber was normally built at one end of a long cairn. This type of tomb dates to the Neolithic Period from 3800 to 3200 BCE.