( 481 ) 
Some fifteen Mounds in Friesland and Groningen have been examined 
by Mr. van Giffen. 
Hoogebeintum. On the Mound lies the churchyard, which is very 
high in itself, and on this the church. The height of the real Mound 
fe 5.80 m. -f A.P. north-west of the church . x ) The Mound must be 
1500 years old at least, and the church not less than 700 years, 
for it was originally built of Tuff-stone, and not before 1200 after 
Christ bricks came into use as buildiug material, of which the newer 
parts of the church are composed. The Mound is one of the highest, 
so we may safely assume that it cannot have been higher after 800. 
The boundary of the grave-yard (found in the Mound) lies at the 
edge of the Mound, at ± 7, m. above A.P., and as the relics of 
this grave-yard date' from the Merovingian time of 500—750 after 
Christ, this grave-yard can be no Older than 1500 years. Now the 
Mound-earth of this Mound does not go any deeper than ±0,3 m. 
above A.P. 
The foundation of this Mound consists partly ot sandbanks in layers 
running from the north to the south, and which have been, washed 
ashore from the north-west. The height of these banks (which clearly 
show “kwelder” vegetation) is from 0,10 to 0,60 m. -f- A.P. 
If the lowering of the ground under the Mound had only amounted 
to 1 mm. a year, it would have amounted to as much as 1,5 m. 
after 1500 years, and the graveyard would now lie deeply buried 
in the ground. 
In general the relics from the first centuries after Christ occur 
in the oldest Mound-layers, especially those from the Roman era, so 
from the latter half of the first century before Christ, e.g, in the 
Mpund at Besseburen near Beetgum, and also the Saxon urns from the 
Merovingian period. These lowest Mound layers do not lie below A.P. 
or only a little below it. 
The Mound at Baayum. To determine the foundation, the ground 
close by the side of the Mound was investigated. Under the turf a 
layer of “knik” 2 ) was found, which downward gradually passed into 
light yellow sandy soil in layers, and under this bluish sand with shells, 
Scrobicularia, Carduum, Tellina etc. 
] ) The threshold height of the church is 8.50 m. -r A.P.; the highest point of 
the church yard lies at 8.95 M. + AP. This point was formerly erroneously taken 
for the height of the Mound, which was accordingly given as much too high- 
2 ) “Knik” is a clay hardened by mixture with oxyde of iron, and a moist 
situation during a long time. 
