The summer of 1971 was significant for both the Morristown and Newark communities. St. Benedict’s Prep closed in June and Abbot Martin Burne announced his resignation as abbot in Morristown on 1 July. He did not explain his reasons and it was a blow to the community. On 2 August the Chapter elected Leonard Cassell the sixth abbot of St. Mary’s. He was blessed at a simple ceremony at the regular Conventual Mass by Bishop Casey of Paterson on 12 August. He served only four years until May of 1975 when ill health forced his resignation, but during his tenure, he was faced with the issue of the transfer of a number of monks from Newark Abbey, and the task of appointing a new headmaster of Delbarton School. Fathers James O’Donnell was named in 1972.