The site of the burial ground associated with an early medieval keeill or chapel which would have been in use between circa AD500 and AD1000.  Cronk yn How was excavated by J.R. Bruce and W. Cubbon in 1928.   


The area bears evidence of occupation from the Neolithic period onwards, but the mound was built in the 7th-8th century for a keeill. Subsequently a stone building, measuring 6 metres by 2.4 metres, was built. It appears to have been an oratory chapel with associated burials of Irish type, tentatively assigned to the 12th century. 


The position of the keeill was shown by the occurrence of lintel graves and cross-slabs. Ten cross-slabs were found dating to the 7-8th centuries. Many were associated with burials, and three others were incorporated in the later building. 


Not all the burials in the keeill graveyard were of the lintel type. One belonging to the end of the keeill period had an iron knife and 'button' associated with it. Another, possibly a pagan Scandanavian burial with covering slabs, passed beneath the stone building foundations. There was a horse burial on the west side of the mound, represented by the fragmentary remains, but no dating evidence. Iron nails and rivets apparently associated with the burials were of typical 'Viking' date, as were a green glass bead and fragment of a rune-inscribed standing cross also found at this site.