Annadorn dolmen has a large, low, slightly displaced capstone about 65 cm thick covering a rectangular chamber and supported by three stones about 60 cm high. An account of 1802 suggests that it was formerly set beneath a large rectangular cairn 60 ft in diameter and approached by a lintelled passage, so it could be the remains of a passage grave.
Another possible explanation could be that the supporting stones were originally upright supporting the capstone, representing a more typical tripod dolmen. The monument has not been excavated and closer examination would be required to correctly interpret the site. The capstone has many small solution pits on the upper surface, two of which appear to have been enlarged. The 1802 account also says the chamber under the capstone contained ashes and a number of bones.
References:The Clementinum is a historic complex of buildings in Prague. Until recently the complex hosted the National, University and Technical libraries, the City Library also being located nearby on Mariánské Náměstí. The Technical library and the Municipal library have moved to the Prague National Technical Library at Technická 6 since 2009. It is currently in use as the National Library of the Czech Republic.
Its history dates from the existence of a chapel dedicated to Saint Clement in the 11th century. A Dominican monastery was founded in the medieval period, which was transformed in 1556 to a Jesuit college. In 1622 the Jesuits transferred the library of Charles University to the Klementinum, and the college was merged with the University in 1654. The Jesuits remained until 1773, when the Klementinum was established as an observatory, library, and university by the Empress Maria Theresa of Austria.